The Imperial Army

[Meteoric Assault]

And after all, Army is an offensive tool (unlike the Fleet, that has also a defensive role. Ground troops can defend the planets only in a limited way. If the enemy obtains Space supremacy and has (relatively) unlimited time, Ground units are useless. Army is to take/recover planets when you are at offensive in a (again relative) hurry and decide to invade them.

Army is an offensive tool? Justify your argument.

It's (again IMHO) akin of the Pacific War, when ground troops could not really hold the islands/atolls if the fleet was taken away. And even if they did, their positions could just be bypassed and left for latter (with the plus that in Traveller those baypassed points cannot even act as recon bases for the main force).

I think the misapplication of WWII era logistics in the 57th century of "makers" and other scientific solutions is a bit over simplistic.

So, Imperium does not need a strong Standing Army, just the core needed to mobilize it with reservists and imperialized units in a relatively short time (I'd say from 6 months to a year). And, again, that's cheaper to do relatively close to wher you expect the battle lines (though not close enough to be overrun in the initial attack) than in the Core.

Really?

 

[Garnfellow]

Those are counters from IE. The set from FFW have world names on the white on red counters.

That is correct, but the claim was made that all Imperial units from both IE and FFW had world names.

I'm pulling together a list of FFW ground units, but as a couple of people have already pointed out, only 16 Colonial units in that game have world names.

 

[Condottiere]

Their primary function in war is to act as a speed bump, giving the Navy time to concentrate and contain their opposite numbers, and for troop reserves to be deployed to the front.

 

[flykiller]

It's (again IMHO) akin of the Pacific War, when ground troops could not really hold the islands/atolls if the fleet was taken away. And even if they did, their positions could just be bypassed and left for latter (with the plus that in Traveller those baypassed points cannot even act as recon bases for the main force).

jump and the associated delays in communication render this obsolete. in a mass conflict in a traveller setting there would be no "front line" but rather a very broad and permeable "battle zone". any planet with no interdiction force parked there could be reached normally by anything capable of jumping there.

 

[mike wightman]

Some quotes from CT sources, including TTB itself.

The cache of weapons consists of lmperial Army military
equipment.

An lmperial Army veteran character can examine
the letter

A:13 Signal GK

Imperial Army letterhead

A:13 Signal GK

Colonel Sanchex is head of the Imperial Army Intelligence section

A:13 Signal GK

His grandfather, he tells the
group, served in the lmperial Army Quartermaster Corps

TTB

The Imperial Interstellar Scout Service is a major service within the Imperium.
equal in stature to the Imperial Army and the Imperial Navy,

LBB6 Scouts
Add to the above the character cards in Tarsus and Beltstrike where the ex-army characters served as Imperial Army aides to admirals.

 

[Garnfellow]

FFW Imperial Ground Units [1 of 2]

Here's a list of Imperial units pulled from the FFW counters. I'm working off a PDF that was very hard to read, so I would love someone to review the unit designations.

Named colonial units are initially placed at the start of the game; numbered colonial units are reinforcements.

Source	Designation	Size	Type	TL	Full Name
Colonial	3912	Corps	Lift Infantry	10	3912th Lift Infantry Corps
Colonial	3817	Brigade	Lift Infantry	12	3817th Lift Infantry Brigade
Colonial	1385	Corps	Lift Infantry	14	1385th Lift Infantry Corps
Colonial	1920	Corps	Armored Infantry	14	1920th Armored Infantry Corps
Colonial	155	Brigade	Lift Infantry	10	155th Lift Infantry Brigade
Colonial	840	Corps	Lift Infantry	15	840th Lift Infantry Corps
Colonial	9174	Corps	Lift Infantry	13	9174th Lift Infantry Corps
Colonial	Alell	Corps	Lift Infantry	10	Alell Lift Infantry Corps
Colonial	Zivije	Corps	Lift Infantry	11	Zivije Lift Infantry Corps
Colonial	Garda Vilis (GV)	Brigade	Lift Infantry	10	Garda Vilis (GV) Lift Infantry Brigade
Colonial	Equus	Corps	Lift Infantry	11	Equus Lift Infantry Corps
Colonial	Feri	Corps	Armored Cavalry	11	Feri Armored Cavalry Corps
Colonial	Efate	Corps	Lift Infantry	13	Efate Lift Infantry Corps
Colonial	Vilis	Corps	Lift Infantry	10	Vilis Lift Infantry Corps
Colonial	Esalin	Division	Motorized Infantry	8	Esalin Motorized Infantry Division
Colonial	854	Brigade	Lift Infantry	12	854th Lift Infantry Brigade
Colonial	1031	Field Army	Lift Infantry	12	1031st Lift Infantry Field Army
Colonial	2151	Field Army	Lift Infantry	15	2151st Lift Infantry Field Army
Colonial	1671	Corps	Lift Infantry	11	1671st Lift Infantry Corps
Colonial	1871	Corps	Armored Cavalry	13	1871st Armored Cavalry Corps
Colonial	823	Regiment	Armored Cavalry	15	823rd Armored Cavalry Regiment
Colonial	197	Brigade	Lift Infantry	10	197th Lift Infantry Brigade
Colonial	Porozlo	Field Army	Lift Infantry	10	Porozlo Lift Infantry Field Army
Colonial	Porozlo	Field Army	Grav Tank	10	Porozlo Grav Tank Field Army
Colonial	Regina	Corps	Armored Infantry	10	Regina Armored Infantry Corps
Colonial	Mongo	Battalion	Grav Tank	10	Mongo Grav Tank Battalion
Colonial	Extolay	Corps	Lift Infantry	10	Extolay Lift Infantry Corps
Colonial	Yori	Brigade	Lift Infantry	13	Yori Lift Infantry Brigade
Colonial	Jewell	Corps	Lift Infantry	12	Jewell Lift Infantry Corps
Colonial	Porozlo	Division	Armored Cavalry	10	Porozlo Armored Cavalry Division
Huscarle	1st/4518th	Battalion	Elite Armored Infantry	15	1st/4518th Lift Infantry Regiment
Huscarle	2nd/4518th	Battalion	Elite Armored Infantry	15	2nd/4518th Lift Infantry Regiment
Huscarle	3rd/4518th	Battalion	Elite Armored Infantry	15	3rd/4518th Lift Infantry Regiment
Huscarle	4th/4518th	Battalion	Elite Armored Cavalry	15	4th/4518th Lift Infantry Regiment
Huscarle	5th/4518th	Battalion	Elite Armored Cavalry	15	5th/4518th Lift Infantry Regiment
Huscarle	6th/4518th	Battalion	Elite Jump Troop	15	6th/4518th Lift Infantry Regiment
Mercenary	Alpha	Battalion	Armored Cavalry	15	Alpha Armored Cavalry Battalion
Mercenary	Beta	Battalion	Lift Infantry	16	Beta Lift Infantry Battalion
Mercenary	Gamma	Battalion	Lift Infantry	14	Gamma Lift Infantry Battalion
Mercenary	Delta	Battalion	Lift Infantry	13	Delta Lift Infantry Battalion
Mercenary	PSG	Brigade	Armored Infantry	14	PSG Armored Infantry Brigade
Mercenary	Epsilon	Battalion	Lift Cavalry	15	Epsilon Lift Cavalry Battalion
Mercenary	Phi	Battalion	Lift Infantry	15	Phi Lift Infantry Battalion
Mercenary	Psi	Battalion	Lift Infantry	12	Psi Lift Infantry Battalion
Mercenary	Omega	Regiment	Armored Cavalry	14	Omega Armored Cavalry Regiment
Mercenary	SPL	Brigade	Lift Infantry	12	SPL Lift Infantry Brigade

 

[Garnfellow]

FFW Imperial Ground Units [2 of 2]

Source	Designation	Size	Type	TL	Full Name
Regular	x4	Field Army	Lift Infantry	15	x4 Lift Infantry Field Army
Regular	37	Field Army	Grav Tank	15	37th Grav Tank Field Army
Regular	58	Field Army	Armored Infantry	15	58th Armored Infantry Field Army
Regular	132	Field Army	Armored Cavalry	15	132nd Armored Cavalry Field Army
Regular	367	Field Army	Lift Infantry	15	367th Lift Infantry Field Army
Regular	85	Field Army	Lift Infantry	15	85th Lift Infantry Field Army
Regular	821	Field Army	Lift Infantry	15	821st Lift Infantry Field Army
Regular	2012	Division	Lift Cavalry	15	2012th Lift Cavalry Division
Regular	2013	Division	Lift Cavalry	15	2013th Lift Cavalry Division
Regular	3012	Division	Armored Cavalry	15	3012th Armored Cavalry Division
Regular	3013	Division	Armored Cavalry	15	3013th Armored Cavalry Division
Regular	856	Division	Lift Infantry	15	856th Lift Infantry Division
Regular	3614	Division	Lift Infantry	14	3614th Lift Infantry Division
Regular	3612	Division	Armored Infantry	14	3612th Armored Infantry Division
Regular	3613	Division	Armored Infantry	14	3613th Armored Infantry Division
Regular	x54	Corps	Grav Tank	15	x54 Grav Tank Corps
Regular	812	Corps	Lift Infantry	15	812th Lift Infantry Corps
Regular	437	Corps	Armored Cavalry	15	437th Armored Cavalry Corps
Regular	823	Corps	Lift Infantry	15	823rd Lift Infantry Corps
Regular	1081	Corps	Lift Infantry	14	1081st Lift Infantry Corps
Regular	1041	Corps	Lift Infantry	14	1041st Lift Infantry Corps
Regular	857	Field Army	Grav Tank	14	857th Grav Tank Field Army
Regular	85	Brigade	Lift Infantry	15	85th Lift Infantry Brigade
Regular	86	Brigade	Lift Infantry	15	86th Lift Infantry Brigade
Regular	87	Brigade	Lift Infantry	15	87th Lift Infantry Brigade
Regular	88	Brigade	Lift Infantry	15	88th Lift Infantry Brigade
Regular	2122	Regiment	Jump Troop	15	2122nd Jump Troop Regiment
Regular	2123	Regiment	Jump Troop	14	2123rd Jump Troop Regiment
Regular	45	Regiment	Jump Troop	14	45th Jump Troop Regiment
Regular	616	Regiment	Grav Tank	15	616th Grav Tank Regiment
Marine	1931	Regiment	Marine Line	15	1931st Line Marine Regiment
Marine	2091	Regiment	Marine Line	15	2091st Line Marine Regiment
Marine	5722	Regiment	Marine Line	15	5722nd Line Marine Regiment
Marine	8327	Regiment	Marine Line	15	8327th Line Marine Regiment
Marine	1071	Regiment	Marine Line	15	1071st Line Marine Regiment
Marine	8041	Regiment	Marine Line	15	8041st Line Marine Regiment
Marine	3277	Regiment	Marine Line	15	3277th Line Marine Regiment
Marine	6127	Regiment	Marine Line	15	6127th Line Marine Regiment

 

[Meteoric Assault]

Some quotes from CT sources, including TTB itself.

Add to the above the character cards in Tarsus and Beltstrike where the ex-army characters served as Imperial Army aides to admirals.

Well there you Go

I am behind an Imperial army for the rational that Imperial troops need to have their authority emanating form the emperor .... there are several Terran historical examples of the Legal and Command relationship emanating from a central executive authority.

I see the point Will is making though that their is a " National Guard" in the decentralization of command and authority to allow Sector and Subsector Governments react quickly as a "governor would". I would liken these to the Colonial Army that are subject to imperialization.

 

[Garnfellow]

Well there you Go

I am behind an Imperial army for the rational that Imperial troops need to have their authority emanating form the emperor .... there are several Terran historical examples of the Legal and Command relationship emanating from a central executive authority.

I see the point Will is making though that their is a " National Guard" in the decentralization of command and authority to allow Sector and Subsector Governments react quickly as a "governor would". I would liken these to the Colonial Army that are subject to imperialization.

And I think my cursory review of FFW strongly supports both Mike and Wil. We see all of the following: (1) local planetary defense forces raised at whatever TL the local government can manage -- forces that do not really leave their homeworld, (2) colonial units that are raised by their homeworld, but meet some minimum TL or training threshold and are subject to Imperialization and transport off their homeworld, and (3) regular Imperial Army units raised and trained to meet Imperium standards.

This is a stretch, but it appears based on the colonial initial/reinforcement counters, when a colonial force gets Imperialized it assumes a unit number and is ready to ship offworld. In peacetime the 1031st Lift Infantry Field Army might be the "Marz 1st Army," based in Deneb sector, but in times of war it gets designated the 1031st.

 

[Meteoric Assault]

And I think my cursory review of FFW strongly supports (1) local planetary defense forces raised at whatever TL they can manage -- forces that do not really leave their homeworld, (2) colonial units that are raised by their homeworld, but meet some minimum TL or training threshold and are subject to Imperialization and transport off their homeworld, and (3) regular Imperial Army units raised and trained to meet Imperium standards.

JTAS 10 or 12 has an article written my Marc addressing some this which reinforces your point to an extent.

 

[McPerth]

Army is and offensive tool? Justify your argument.?

Their primary function in war is to act as a speed bump, giving the Navy time to concentrate and contain their opposite numbers, and for troop reserves to be deployed to the front.

I tried, but I'll try now to explain myself better (no promises I achieve it).

How can Army units defend space? They can defend planets, but then what? they are bypassed or bombed, with no real hard effect to the fleet (not even real sped bump of any importance).

The only defense Army can offer is to deny the planets themselves to the enemy, but if the enemy really needs them, they wil lbe taken anyway, sooner or latter. Only if they need this specific planet son will they invade them (so giving the defending Armies their defense role), but even this wil lbe avoided if at all posible, as any planetary invasión is a true nightmare. Even Earth, stuffes as much as the Solomani could with troops fell, albeit after long time and many losses (but invading it was a political decisión, as strategically it could probably be bypassed).

Even in this case, though, the army that can really affect the strategical position is the invading one, as the base may change hands, so being the offensive part what can change things.

I guess you have played FFW. Has anyone really used the mobile Army units (counters, as opposite to planetary defense battalions) for defense of any planet? It is truly a waste of them, as they will not hold for any long, while you'll need tham if you go on offensive, either for planetary assaults or as garrissons in conquered planets.

I think the misapplication of WWII era logistics in the 57th century of "makers" and other scientific solution is a bit over simplistic.

jump and the associated delays in communication render this obsolete. in a mass conflict in a traveller setting there would be no "front line" but rather a very broad and permeable "battle zone". any planet with no interdiction force parked there could be reached normally by anything capable of jumping there.

Yes, of course there are differences, and any any semblance must be relativized, but there are similitudes nonehteless.

In both cases, the main elements of the war were the Navies (forgive me to dismiss the air power of this discussion, but it has no real equivalent to Traveller setting), while the ground troops were only used to take/defend/garrison the bases the navy needed, so making them ancilalry of the Navies. And in both cases this gave place to not having hard front lines, but sea battle zones that were contested, with the bases held by the ground units used to move this battle/contested zone.

Of course supply differences were many, but also was its effect in the global picture if bypassed. While in Pacific War those bases could be used as scouting bases and listening posts, with the knowledge achieved immediatly given to the HQ, this is not true in Traveller setting.

Really?

I believe so. If you'e going to offensive, you have the preparation time to put those units to full mobilization/complement status, and if you're i ndefensive stance, you won't need them at this full status until you contained enemy forces and begin counteroffensive.

 

[McPerth]

Some quotes from CT sources, including TTB itself.


Add to the above the character cards in Tarsus and Beltstrike where the ex-army characters served as Imperial Army aides to admirals.

And which one of those cannot be applied to an HQ & Huscarles style Imperial Army?

See that there are more references to IA HQs and special units than to its Infantry or Armor ones, so, again IMHO, coherent with this kind of Army...

 

[mike wightman]

As I have posted several times - I have no problem with the idea that on the frontier the Imperial Army drafts colonial army units, mercenaries, peasants with pitchforks if necessary.
I view it as similar to the Roman army (Traveller's Imperial was originally envisaged as based on the Roman model according to interview sources) in that there were regular legions - regular Imperial Army - and auxiliaries raised from the provinces - colonial forces.

I find it odd that the Imperium doesn't aid in the economic development of worlds or the enrichment of the world population living standards, but quite happily drafts their armed forces in times of conflict. Must be a pretty persuasive treaty negotiator... (see AotI)

 

[kilemall]

But even this TL15 multi-billion pop Core World can be contained by the Navy if it becomes rogue while Ground troops are assembled/mobilized. it rebellion would not be critical to the Imperium as lon gas it does not spread (and, again, that's IN's task to avoid, not Army's.

IA's job is going to be showing up for the long haul with the BIG formations and routing out the rebellious infestation, for good. IN is to quarantine, but you don't want to tie up a fleet for 6 months/year while cadres build the Field Armies and what not, THEN transport them. You want fast resolution so those hideously expensive formations are putting down 2-3 rebellions per year and have enough give to shift things frontierward at need.

What I see as a primary need is DETERRENCE, and that means relatively fast reaction so a rebel planet cannot dig in and use the populace as hostage and time cost sink, whether frontier or core.

Or worse, other planets revolt while the Imperium is busy with the first one.

The mix will be different, a lot higher percentage Marine and merc and colonial for the frontier, but to deter a Core World means being able to put on an IE level of effort, fast. That means big formations for the big pop sectors. Imperial Army formations.

And any rebellion(going rogue planet is probably more easy to occur in the frontier than in the Core, where any planet feels (probably) more Imperial loayalty (even if only due to not knowing anything else), knows that it ahs no outside support and is (again probably) in a more stable zone.

I would agree with the characterization, but again big pop x fast restoration = huge army within the sector.

And think what would the Core pople, that to a point they feel secure and Imeprium Loyal, of having to maintain such an enormous aremy where it is not expected to be used (except maybe against themselves, as you say). Will they see it as a good way to expend the taxes?

One of the major elements we may be missing here is the NATURE of core worlds.

Because of the bigger pop, they are going to be all those 9ABCD places with unpleasant law levels.

A revolt on such worlds are going to be either discordant protests against such hellholes, in other words against the government not the Imperium, or topdown leaders of said authoritarian governments against the Imperium.

In both cases, the objective is rapid restoration of order, trade and taxation. One 20 billion TL15 planet translates into an entire frontier subsector's worth of revenue using the Striker/TCS valuations, and arguably a more nuanced model with trade routes disrupted at the least would cause other neighboring TL15 billion+ pop worlds to sag in taxation as well.

Of the two types, the second is the more dangerous, as they will be the ones with the guns, access to fighting ships and industry, organized armies, etc.

Probably the most dangerous revolts are by Charismatic Dictatorship/Oligarchys, in that case the populace could be supporting an organized topdown effort and it really may be an IE situation, requiring a nuclear response to avoid consumption of whole armies.

Otherwise the citizens are likely being forced to revolt by unbearable oppression or by topdown order, and will be just as happy to not support the current leadership and get back to work if the government falls to the next one. Rescuing those people, stopping political contagion and getting the revenue stream going again is Job One.

Having an IN fleet sit around while you raise an army for a year is NOT cost effective.

What IS, is

• using your extant hard-hitting Marine units for situations where rapid decapitation of the top echelon of government leaders is doable,
• commit the Imperial Army assets in the sector to bulk up the Marine cutting edge for both invasion and garrisoning,
• get the Marines and IN free and out of there ASAP for return of rapid reaction capability, and
• meantime use the time from the start of the crisis to raise your new replacement Army formations for the NEXT potential revolt in the sector.

Result, quick revolt crushing, only six months or so of vulnerability while assets are committed to the crushing and then moved out, Imperium shows resolve which deters or cows anyone else thinking of following suit, 2/3 of responses (nuke, Marine decapitation) are available again at the earliest possible time frame, the invasion option will be ready again in a year while restoration of taxes pays for the whole operation.

Time value both politically and economically, that's what people are missing about Core World asset management.

But it requires a large standing army, and that this army does not get sent off in bulk to the frontiers except for something like IE.

I do believe the Imperium would economize in the Spinward Marches- as of the classic period, it would not pay for huge formations by itself and is justified only as a means of border deterrence and not having to fight the next generation's battles closer to the Core base.

And of course the moment the crisis is over (frontier or Core revolt) and more normal force can be maintained, there would be a LOT of mustering out, hence a lot of those 26 year old enlisted and junior officers to recruit for all those merc forces.

 

[kilemall]

Anothre point is that, unlike the Navy, that mostly stays in orbit, the Army units have to interact more closely with local population, so knowing something about it is a true bonues. And that cannot be achieved from a year distance, it must be closer.

And after all, Army is an offensive tool (unlike the Fleet, that has also a defensive role. Ground troops can defend the planets only in a limited way. If the enemy obtains Space supremacy and has (relatively) unlimited time, Ground units are useless. Army is to take/recover planets when you are at offensive in a (again relative) hurry and decide to invade them.

I refer you to the time/space/resource play of IE and it's predecessor battle example, the Alamo and the companion battle San Jacinto.

Space Alamos can be a form of winning too. Although Santa Anna's naval supply problems are often not understood by most people that led directly to San Jacinto. Don't think there is a SRW San Jacinto, but then again the Solomani aren't plucky lucky Texans.

As to the planetary defense side of things, that is a political play vs. resources sort of thing. Might get away with planetary defenses if they are deep enough and the enemy does not want to slag the planet, or does not have the ships to lose, otherwise it's an invitation to being nuked or bombarded to no good purpose.

It's (again IMHO) akin of the Pacific War, when ground troops could not really hold the islands/atolls if the fleet was taken away. And even if they did, their positions could just be bypassed and left for latter (with the plus that in Traveller those baypassed points cannot even act as recon bases for the main force).

I refer you to Wake Island, where the Marines held off the Japanese by having artillery that outranged the destroyers, the IJN had to bring in additional assets to finish the job.

Similarly, at Rendova the Marines were dropped on the beach which the Japanese figured was a wasted out of range jaunt and ignored it. Until their airbase at Munda came under fire by 155mm artillery at Rendova, first time the 155 was used against them.

That being said, IA assets aren't space control assets, they are ground control assets, could cause serious difficulty for using the planet as a serious base but no one would confuse them for holding off a fleet- indeed, in most cases if a large IA formation was untenable, they would pull that formation out

Unless it was like the Philippines and judged more important to leave the army in place for showing political commitment/long-term support purposes rather then pull it out in time.

So, Imperium does not need a strong Standing Army, just the core needed to mobilize it with reservists and imperialized units in a relatively short time (I'd say from 6 months to a year). And, again, that's cheaper to do relatively close to wher you expect the battle lines (though not close enough to be overrun in the initial attack) than in the Core.

Yaaaaa. No.

Just one quick back of the envelope calc- TCS taxation is 500 Cr per citizen, modified by TL adjustment and government modifier. TL15 is valuated at 100%, we'll skip the GM which is mostly favorable to greater revenue, so our 20 billion pop planet is yielding 10 trillion credits.

Even assuming the 'naval tax' is spread out something like Striker or Aramis' examples, that's 3 trillion per core planet for IN formations, several times the classic TCS naval formation.

Figure something like the US expenditure in WWII where the army was just 13% of the whole thing, and you still have more then 1 trillion in revenue to justify a Very Large Army formation.

Mitigate that expense against say 10 such planets in a Core subsector, and you have enough revenue to have immediate reaction forces close by, fund big formations at the sector level, and still send half of it off to the borders to do their job, which is to keep the wolves (figurative or literal) from messing up the goose that lays the Core golden tax eggs.

 

[flykiller]

What I see as a primary need is DETERRENCE

ah. a primary consideration and a good justification for a standing army. but only at first glance.

internally, deterrence will take the form of good governance, decisive police action, and if necessary some covert actions to co-opt or cut off rebellions before they happen. if any situation ever deteriorates to the point where an imperial army is required to restore a world to the imperium then you can bet some noble will be held accountable for letting things get so bad.

externally, deterrence will take the form of a sufficient and properly disposed navy preventing the insertion of any hostile armies in the first place. again, the action will be decided by the navy, not on the ground. any ground action that does take place will be like iwo jima - one side is enforcing an inevitable victory, and the other side is resisting an inevitable defeat.

now at a serious point of contention, such as jewell, there will of course be a large standing army, but only as a defensive backup measure to supplement the front line naval force and to buy time to allow the arrival of sufficient naval reaction forces.

transporting and landing any army offensively in the face of significant naval opposition would be costly to the point of prohibition.

 

[Enoki]

Tactics in the Imperium would be very different from those of a large conventional war of the Industrial Age (~ TL 4 to 6 per MT, 4 to 8 CT). Their situation more closely resembles the US "Island hopping" campaign of the Pacific War.

That is, individual planets and systems could be considered similarly to islands and atoll / island groups that are for all intents isolated from other islands and atolls / groups. The Imperial Navy is the critical means to defend and take these in a war. They would need to prevent the opposing navy from gaining in essence sea control (well space control in this case) of the system or gain space control in the case the Imperial Navy was attacking.
Once that is accomplished, the Imperial Navy could bring in sufficient marines to take the various planets and satellites in the system. They could systematically eliminate these as they control the space in between and can prevent the defense from moving troops and reinforcing the system.

The Imperial Army, or for that matter, anyone's army in that situation is reduced to basically a defense force. You'd need two major types of troops to do this: The first amount to fortress troops. You might call them "coast defense" troops or in this case "planetary defense" troops. This type would man heavy batteries of weapons and shields to defend the planet along with probably manning any orbitals and planet defense ships (system defense boats). That way the planet's defenses are coordinated under a single command.

The second part of an army would be the ground forces that support the above fortress troops. These units are equipped for field operations and can fight a mobile battle but still are mainly defensive troops as their purpose is to repel the enemy's marine landing force if it manages to get on the planet. I could see them as heavy weapon heavy in terms of equipment. Artillery and crew served small arms capable of massive firepower would be available in large numbers to them. They'd have some degree of fortification to operate from making the opposing navy's task of taking them out difficult to accomplish by mere bombardment of the planet.

How much of this would be on any particular system would largely depend on where the system is. What I described above would be a border region with a potential serious enemy.

Not every system on a border need be so heavily defended. Ones with marginal value or in poor strategic locations might be ignored or lightly defended.

The interior of the Imperium (or other large empire) wouldn't need this sort of serious defensive capacity for the most part. There might be older fortifications on planets that previously were border regions but "safe" systems well behind any potential front are likely to have far less defensive capability simply because it really isn't needed and costly to maintain.

Here, the Army provides what are "colonial" troops. That is units that are equipped to deal with an insurrection, minor war in the system, terrorism, and guerrilla warfare. They have a few armored vehicles, a bit of artillery, and are equipped well enough to outgun some pirates or irregulars with so-so small arms and equipment.
Many such worlds might have sufficient planetary defenses to take on a couple of smaller ships... say a couple weighing under 10,000 tons at most and primarily armed with turret weapons and a few bays. That eliminates any possibility of piracy in such a system. That might require a few hundred well trained troops to maintain and operate but isn't onerously expensive.
They need only hold the main world and any important secondary worlds. Most of the planets and satellites in the system wouldn't be occupied at all.

The Imperial Navy could respond to any serious threat to such a system while the local army units try and hold out to await their arrival.

So, one could expect relatively short, very intense, and casualty heavy battles in a war with periods of inaction in between while both sides lick their wounds and reset for the next system battle. A sustained offensive would require a massive fleet train to keep the starships and their marines operational as they move forward from system to system.

If the Imperial Navy were a truly offensive force it would have to have a considerable number of tankers, supply ships, troop transports, and auxiliary maintenance vessels to support operations. It would have to be able to bring a very good class A starport with it as it advanced, one capable of supporting the fleet of ships being used in the operation.
They couldn't rely on being able to capture enemy port services intact or easily repaired. Instead, they'd be planning on the enemy destroying these before they were captured and therefore needing to bring their own.

All of that also implies that the Imperial military is really, really good at civil engineering and construction. I'd posit that many of the Army units would be essentially construction oriented combat engineers, something like the USN SeeBees are.

 

[flykiller]

That is, individual planets and systems could be considered similarly to islands and atoll / island groups that are for all intents isolated from other islands and atolls / groups.

the correspondence, while striking at first glance, fails when jump is considered. the only way to cut off any individual system is either 1) to station an interdiction force on top of it, or 2) to capture and deny transit in any system within jump range of the system in question. 1 is a siege operation requiring significant forces, and 2 seems impossible in most circumstances - attempting to deny transit in such a large area will result in critically over-extended naval forces subject to defeat in detail in any location. a system cannot be "isolated" without strenuous effort and resource allocations.

 

[kilemall]

internally, deterrence will take the form of good governance, decisive police action, and if necessary some covert actions to co-opt or cut off rebellions before they happen. if any situation ever deteriorates to the point where an imperial army is required to restore a world to the imperium then you can bet some noble will be held accountable for letting things get so bad.

Of course, talking and diplomacy and deals and bribery are almost always infinitely cheaper and better, and ensure that all-important tax/trade flow, moreso then fleets and armies.

They are an expensive burden. Until you need them.

externally, deterrence will take the form of a sufficient and properly disposed navy preventing the insertion of any hostile armies in the first place. again, the action will be decided by the navy, not on the ground. any ground action that does take place will be like iwo jima - one side is enforcing an inevitable victory, and the other side is resisting an inevitable defeat.

Largely the case, I am not necessarily arguing otherwise although Enoki's PD force/basing case is very strong.

I am saying that Iwo Jima type delays can be valuable, again reference Alamo in conjunction with cutoff of Mexican seaborne supplies yielding San Jacinto, and relatively cheap buying time compared to fleets and above all their multi-year construction time.

now at a serious point of contention, such as jewell, there will of course be a large standing army, but only as a defensive backup measure to supplement the front line naval force and to buy time to allow the arrival of sufficient naval reaction forces.

transporting and landing any army offensively in the face of significant naval opposition would be costly to the point of irrelevance.

None of that argues against what I am postulating the nature of the bulk of the Imperial Army is, back at the Core Worlds, and why we wouldn't see it in full force at the frontiers except in emergencies.

 

[flykiller]

If the Imperial Navy were a truly offensive force it would have to have a considerable number of tankers, supply ships, troop transports, and auxiliary maintenance vessels to support operations.

I studied this extensively. unless one posits nearly unlimited shipyard capacity, or posits ideal force compositions in defiance of any construction logistics, it can't be done. construction of combat forces sufficient for some guarantee of naval victory displaces construction of most support ships. imtu support ships are built mostly by porozlo (tech 10) and junidy (tech 9), but all other yards are devoted to combatants. at this spinward-marches ratio of combatants to support it's possible to supply some significant offensive task forces, but not generally, and certainly not enough to transport any full-scale army.