Imperial Crust Defence or Defence in Depth

[Matt123]

http://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=10734685

There was a discussion on here a while ago on the Imperial Doctrine of Crust Defence, with some suggesting that it is absurd that the Imperium would have adopted such a defensive strategy.

If you don't already know, a Crust Defence is one where the majority of your assets are placed in the front line. Picture trench warfare in WW1 or the French defensive positions in 1939. It provides a firm and obvious deterrent to your opponent, but if the other side is determined, you surrender the strategic initiative. Once the "crust" is penetrated you have to pull back your forces before you can re-organise your defence. Concentrating your forces is extremely difficult starting from a crust defence and your attacker will have concentrated his attack forces.

A Defence in Depth involves using light screening/tripwire forces on the frontier and concentrations of assets out of first strike reach, behind the front lines. In the event of penetrations, your forces are already concentrated and only have to move forward. The downside however, is that your borders look weak to the casual observer, leading to concerns at home and overconfidence in your neighbours. (both examples are overly simplified of course).

The link is to a NZ Herald article looking at Australia's proposed new Crust Defence policy. It gives many sound reasons for the adoption of a crust defence, mostly though it relates to being "in your face" to future protagonists and you can also read into it, that it is comforting to the population and businesses operating from home.

As a strategist though, I can picture the Chinese, Indonesian & Indian strategists reading this article & rubbing their hands together at the thought! Thats not to suggest they are going to invade, just that it is the military's job to have an already considered plan IF the politicians wish to invade. (Just as its the Ozzie militaries job to have a defence plan).

So back to the Imperium. Why does doctrine change from a good one to a bad one? One answer is that long periods of peace remove veteran, respected warfighters from the decision making process. Politicians instead make the decisions and among their toolset, they have and use regularly posturing and sabre-rattling. Never mind it weakens the warfighting position, the aim of politics after all is not to go to war...

 

[HG_B]

As a strategist though, I can picture the Chinese, Indonesian & Indian strategists reading this article & rubbing their hands together at the thought!

Not really. None of those 3 have any ability to invade.

 

[Dragoner]

IIRC the Imperium used the crust defence when it outclassed it's enemies of the Vargr and Zhodani so they would have trouble breaking through the main line of defence. IMO now, the Imperium follows a Mobile Defence posture as it makes it easier to go on offensive, which of course the down side is that one has the fortify strategic systems better to withstand longer sieges.

A swift and vigorous transition to attack-the flashing sword of vengeance-is the most brilliant point of the defensive.
-Carl von Clausewitz, On War, 1832


http://www.globalsecurity.org/military/library/policy/army/fm/3-90/ch10.htm

 

[The Oz]

IIRC the Imperium used the crust defence when it outclassed it's enemies of the Vargr and Zhodani so they would have trouble breaking through the main line of defence. IMO now, the Imperium follows a Mobile Defence posture as it makes it easier to go on offensive, which of course the down side is that one has the fortify strategic systems better to withstand longer sieges.

A swift and vigorous transition to attack-the flashing sword of vengeance-is the most brilliant point of the defensive.
-Carl von Clausewitz, On War, 1832


http://www.globalsecurity.org/military/library/policy/army/fm/3-90/ch10.htm

That's correct, as put forth in Supplement #9. That supplement also mentions that at the same time, the Imperial Navy also shifted battlerider squadrons into the reserve fleets, thanks to the difficulty battleriders have in withdrawing from action in the event of enemy superiority.

Some people have conflated these two statements together to say that this was a coordinated change in strategy by the Imperial Navy; however, there's nothing in Supplement #9 to prove that; the reasons given for the two changes are different, and the results of the two changes are different.

That said, taken together, they produce a massive change in Imperial deployments:
1) Before the 4th Frontier War the Imperial Navy is (presumably) spread out in a large number of fleets close to the frontier, each fleet composed of a mix of battlerider and battleship squadrons.
2) After the 4th Frontier War, there are fewer front-line fleets (one per high-population planet?) equipped only with battleship squadrons, while large fleets of battlerider squadrons are concentrated back from the frontier (at Deneb) waiting for the word to move up and counterattack.

 

[Matt123]

Not really. None of those 3 have any ability to invade.

Lol. Any scenario where you voluntarily put your combat assets within alpha strike range, leaves you open to massive force reductions in the first few hours.

After that the neighbors may well be competitive.

But I doubt there is any political will on the part of those three countries to invade anyway, they have enough problems at home without adding more. In this environment a "keep your hands off our off-shore assets stance" is quite possibly prudent. It still amounts to a crust defence however and demonstrates one way such a defensive doctrine comes about.

 

[HG_B]

Lol. Any scenario where you voluntarily put your combat assets within alpha strike range, leaves you open to massive force reductions in the first few hours.

Irrelevant to the sit. As I correctly stated, none of those 3 countries have any capability to invade Australia.

 

[aramis]

No further discussion of the China/Australia situation. It constitutes politics.

 

[Dragoner]

That's correct, as put forth in Supplement #9. That supplement also mentions that at the same time, the Imperial Navy also shifted battlerider squadrons into the reserve fleets, thanks to the difficulty battleriders have in withdrawing from action in the event of enemy superiority.

Some people have conflated these two statements together to say that this was a coordinated change in strategy by the Imperial Navy; however, there's nothing in Supplement #9 to prove that; the reasons given for the two changes are different, and the results of the two changes are different.

That said, taken together, they produce a massive change in Imperial deployments:
1) Before the 4th Frontier War the Imperial Navy is (presumably) spread out in a large number of fleets close to the frontier, each fleet composed of a mix of battlerider and battleship squadrons.
2) After the 4th Frontier War, there are fewer front-line fleets (one per high-population planet?) equipped only with battleship squadrons, while large fleets of battlerider squadrons are concentrated back from the frontier (at Deneb) waiting for the word to move up and counterattack.

One could look at the idea in two different ways, one would be to look at it as a strategy for the Imperium as a whole, or how they manage their defences in a border region. As a whole, I would think the Imperium does keep it's more powerful fleets near the core under direct control of admirals close to the Emperor, thus trying to avoid the situation of Plankwell leading a frontier fleet back to the core and claiming the throne. Better to trade space for time and another thing is to look at that it is the Imperial fleet itself that constitutes a large threat to the Imperium.

As far as border defenses go, I looked at FFW, and other materials like SMC and even local fleets are kept back and have to be constituted in case of war. Which seems to say the Zhodani have changed tactics from just hitting border areas, to deep thrusts at worlds like Rhylanor. Though the FFW seems rather an abortive war and it would make sense that the best defense, regionally would to be to go on the offensive against the Zhodani, Solomani, Vargr, etc.; something the Imperium has the power to do and IMTU, after the rebellion, it does.

 

[pmbnss]

http://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=10734685
Why does doctrine change from a good one to a bad one? One answer is that long periods of peace remove veteran, respected warfighters from the decision making process. Politicians instead make the decisions and among their toolset, they have and use regularly posturing and sabre-rattling. Never mind it weakens the warfighting position, the aim of politics after all is not to go to war...

As you say, doctrine changes when the decision-making priorities shift from defense to political need. Defense in depth is a great strategy for the polity as a whole against an enemy of similar capabilities, but not necessarily for the locals "on the border" who can expect to be overrun, held hostage, annihilated, etc., or however the war evolves, or if the enemy is of much lower capability.

On the political side, your industrial world noble will likely be angling for large defense contracts for his megacorporation buddies (bringing home the bacon), and the creation of large "crustal" style defense of the planet, despite the larger strategic need for a defense-in-depth. Other possibilities may include ensuring loyalty of Imperial border worlds by "showing the flag" with a strong garrison, particularly if the world is high-pop and capable of building significant planetary navy and system defenses that might challenge an Imperial Batron.

Another possibility (used IMTU) is that the Imperium actually encourages small wars as a social mobility "pressure valve." Non-nobles may become nobles through military service - particularly in the Navy and Marines, but to do so requires conflict. After several generations, the ever increasing number of second and third sons/daughters striving for social mobility creates instability within the Nobility, leading to civil war. Thus MTU Imperium actively encourages small border conflicts every couple of generations, to "cull the noble herd" and to create opportunities for the ambitious. Total war and utter defeat of the "barbarian" empires would end the cycle, so a crustal defense is used to give the barbarians a chance, and any serious threat to the Imperium is mitigated by very strong mobile forces at kept at the Core. Very similar to the way the Crusades were encouraged as a means of sending a noble away in the hopes that he was killed and the Crown or his neighbors could gain his lands.

Third, a crustal defense might be a very useful defense against Vargr incursions/looting, or against Sword Worlds expansion, but at the same time be a poor strategy for dealing with the Zhodani. In the areas of SM where the Zhos and Vargr are nearby, a crustal defense may used to mitigate the effects of Vargr invasions, despite the cost, with the full understanding that this will in no way slow the Zhos.

 

[McPerth]

There was a discussion on here a while ago on the Imperial Doctrine of Crust Defence, with some suggesting that it is absurd that the Imperium would have adopted such a defensive strategy.

(...)

So back to the Imperium. Why does doctrine change from a good one to a bad one? One answer is that long periods of peace remove veteran, respected warfighters from the decision making process. Politicians instead make the decisions and among their toolset, they have and use regularly posturing and sabre-rattling. Never mind it weakens the warfighting position, the aim of politics after all is not to go to war...

Well, I may be wrong, but I see the Imperial defense policies more as a mixted plans than a Crust Defence, as they have the BB BatRons as Crust Defence, but most of BR BatRons are as deep reserves, indicating a Defence in Deep is also planned.

For a true Defence in deep (AFAIK, I'm not in the military), you need reliable and quick communications, as you must identify the enemy thrust and be able to react quickly to it, either by confronting it or by allowing it a limited penetration while threatening their flanks, hoping to breack it and leave the spearhead cutt off (as in Stalingrad, or to a lesser scale in several Pusan Perimeter engagements).

As this is not a viable options when you intelligence is (in the better circumpstances) two weeks old, and the fleet you know to be in system X may well be two jumps away when you arrive, I guess true Defence in Deep is not an option, needing some Crust Defence to hold them and buy time as the deep reserves close and activate Defense in Deep, when enemy thrusts are identified and time built up to react to them.

That's not to deny one of the first steps any military forces must do when engaged in a war if they have spent much time in peace is to purge the high command of all rotten wood acumulated while positions are earned more for political/administrative skill than for military one.

 

[Enoki]

A crust defense with mobile reserves directly behind it would be the best strategy from a strictly military point of view based on the way Traveller works. Thus:

1. The maximum jump is 6. Therefore, any attempt at an invasion / attack cannot move much beyond the first 6 hexes into the Imperium or to planetary systems beyond that depth. We might consider 12 hexes to be the practical limit assuming that the attackers bring their own fuel for a second jump with them.

2. Jump 6 in itself imposes limitations on ship design unbalancing it in favor of jump and engines. This means less of other stuff.

3. Without some plan to take and hold planets in the rear of a deep infiltration attack that operation will peter out on its own simply through lack of support and reinforcement. This is to say that within the Traveller system a "blitzkrieg" type war is not very possible.

The result of this is that the best defense for a large empire is to build the equivalent of a Magniot Line. Systems within 6 to 12 hexes of a threatened border are fortified with ground and system defenses along with holding some ships in each. Behind these positions are larger fleets stationed at intervals that can jump to threatened systems within one or two jumps.

A defense in depth makes no real sense as Traveller lacks the strategic mobility of forces to make it necessary.

 

[rancke]

The available evidence shows that in 1105 the Imperium had a fleet in most subsectors (though not all -- Lanth and Aramis does not seem to have one, and the forces in the rimwards sectors of Mora, Trin's Veil, and Glisten are not specified) plus major reserves in Corridor. Post-5FW deployment has a fleet in every subsector (not necessarily with the same force level, though) and 12 extra fleets stationed in Corridor.

Individual deployment within each subsector is unclear. The Imperial fleets could mainly be concentrated at the subsector capitals. OTOH, Efate definitely had considerable Imperial assets stationed.


Hans

 

[Dragoner]

A crust defense with mobile reserves directly behind it would be the best strategy from a strictly military point of view based on the way Traveller works. Thus:

1. The maximum jump is 6. Therefore, any attempt at an invasion / attack cannot move much beyond the first 6 hexes into the Imperium or to planetary systems beyond that depth. We might consider 12 hexes to be the practical limit assuming that the attackers bring their own fuel for a second jump with them.

2. Jump 6 in itself imposes limitations on ship design unbalancing it in favor of jump and engines. This means less of other stuff.

3. Without some plan to take and hold planets in the rear of a deep infiltration attack that operation will peter out on its own simply through lack of support and reinforcement. This is to say that within the Traveller system a "blitzkrieg" type war is not very possible.

The result of this is that the best defense for a large empire is to build the equivalent of a Magniot Line. Systems within 6 to 12 hexes of a threatened border are fortified with ground and system defenses along with holding some ships in each. Behind these positions are larger fleets stationed at intervals that can jump to threatened systems within one or two jumps.

A defense in depth makes no real sense as Traveller lacks the strategic mobility of forces to make it necessary.

Maximum Jump for war fleets is better considered to be 3 or 4 imo, but given say two weeks to a month initiative for the attacker, depth of the battlefield will still be 12-16 parsecs deep. It really makes sense then to have a ton of scouts floating around everywhere as well as to spy on enemy deployment. If the enemy begins to mobilize, they the Imperium begins counter mobilization to effectively neutralize the threat. In the end, I would think the Zhodani would goo for main fleet engagements, as attritionary warfare would favor the Imperium due to it's size and societal structure being less rigid than the Zhodani. A Zho Prole would remain a Prole, no matter how hard they fought, how good of ships the designed or how productive they were on the factory floor, sort of like Czarist Russia. So the Zhodani lack stamina in warfare, too hard and the proles revolt. The Imperium on the other hand, can trade space for time to get fleets into the marches or whatever hot spot, and in many ways, depend on solid resistance of Zho occupied worlds as well as being welcomed as liberator when they return.

 

[warwizard]

I think that the idea that a fleet in a system can prevent a fleet from passing through is unrealistic, as well as the idea that a line of communications has to be maintained or immediate and dire things happen.
Contact and engagement with the opposing forces is what consumes your combat load and requires large volumes of cargo sapce for munitions and spare parts. Freighters would accompany the fleets and provide two or more additional combat loads for the fleet.
The goal of a raid would be to destroy the other side's ability to perform maintence, and produce large scales of munitions. An initial Zhodani campaign into the spinward marches should start with raids at Depot/Corridor, Glisten, Trin's veil, Lunion, Rhylanor, Efate and so on, denying the imperials the means to support large forces. Imagine the damage a single light crusier could do to mophballed vessels in orbit at a major naval base. It's the taking of high tech high population worlds that will destroy whole fleets, and should not be done until after the area has been isolated and space supremancy established over the quadant, if not the whole subsector.
FFW played under these guidelines looks totally different, the intruder jumps to presurveyed fuel sourses in the outer system, and refuels and departs. and the native forces cannot respond in time to prevent access to the oot cloud bodies, no combat happens untill the intruders desire an engagement, and even then it's not generally a blood bath, but rather a two week process of cat and mouse prepositioning sensor drones and preparing the the attack, which should be more like the first day at Shiloh than the third day at Gettysburg.
Overriding all of this should be the war aims of the attacker, it has already been noted that attritional warfare would favor the state with more staying power, so a reasonable war aim of the Zhodani might be to attack and cause damage to 3 to 5 high population worlds and then negoiate a quick peace.

 

[rancke]

Overriding all of this should be the war aims of the attacker, it has already been noted that attritional warfare would favor the state with more staying power, so a reasonable war aim of the Zhodani might be to attack and cause damage to 3 to 5 high population worlds and then negoiate a quick peace.

I don't think I can prove it with actual canonical quotes, but my analysis of the Zhodani goal is that they wanted to capture several worlds in the Duchy of Regina plus Rhylanor and then trade back Rhylanor to the Imperium in return for letting the Duchy of Regina become a neutral independent.


Hans

 

[warwizard]

Hans, it's implied in the victory conditions in FFW. Capture Victory points (POP + TL of captured worlds)
Having said that, it's a board game, and has to have a method of measuring victory. Perhaps a rewrite to allow the Zho player to select among war aims would change the game into a more of a strategic simuation, rather than an operational one.
This thread is discussing Strategy rather than operations, so our FFW game is slightly flawed as an informer of strategy.

 

[Dragoner]

If one splits up their fleets to take on other missions, such as reducing worlds (which would probably be identified and heavily fortified) one would run the risk of having your fleets defeated in detail. Spliting up your forces is often considered bad in strategic situations, the whole "punch with the fist, don't tickle with the fingers" maxim. The best is to catch the Imperial fleets forming, defeat them in detail and then reduce the worlds at leisure, though wanton destruction would probably have a negative effect of forcing the Imperium to go on a major offensive or lose political clout in the region, notably Norris would feel the heat. I think the Zhodani war aims would be to get the Imperium to actually create a demarcation line of what worlds were for the Zhodani to colonize and what for the Imperium, but the Imperium's attitude is to laissez faire to actually sit down and do something like that, plus time is on the Imperium's side. The Imperium can also, being pluralistic, convert Zhodani settled worlds, with which the Zhodani society being monolithic, can't really do as easily.

 

[McPerth]

So the Zhodani lack stamina in warfare, too hard and the proles revolt.

I don't believe the proles in Zhodani consulate would revolt so easlily. They are made happy with their place in society, and the apearance of rebel cells is quite unlikely (IMO) to develop due to the Tavrchedl' monitoring.

The goal of a raid would be to destroy the other side's ability to perform maintence, and produce large scales of munitions. An initial Zhodani campaign into the spinward marches should start with raids at Depot/Corridor, Glisten, Trin's veil, Lunion, Rhylanor, Efate and so on, denying the imperials the means to support large forces. Imagine the damage a single light crusier could do to mophballed vessels in orbit at a major naval base.

I can accept initial raids on Efate, Lunion, Glisen, and even Rhylanor or Trin's Veil, (though those last ones are difficult to arrive unnoticed to their goals), but Depot/corridor is sure too far for those kind of raids.

Not only the possibility to arrive there is too slim (IMO) and I guess most of mothballing places are heavily patroled, but once sent it would be impossible to abort them (if plans are changed in the 2-6 months needed to arrive) and timing the raids is impossible.

If those raids are done before war is known (as they should be to be effective), they could arise a popular response not unlike that of Pearl Harbour, thus raising the Imerium resolution to wage war (and the Zhodani, with his superior knowledge of psicology sure know that).

Overriding all of this should be the war aims of the attacker, it has already been noted that attritional warfare would favor the state with more staying power, so a reasonable war aim of the Zhodani might be to attack and cause damage to 3 to 5 high population worlds and then negoiate a quick peace.

In Rebelion Book (MT) is stated that the Frontier Wars had no expasionist goals, but they were preventive wars to keep the Imperium from further expansion in the Zhodani (Core/Spinward) direction. I don't think they would really permanently occupy Imperial HiPop worlds.

 

[kafka47]

[FONT=arial,helvetica] Quote:
Originally Posted by warwizard
Overriding all of this should be the war aims of the attacker, it has already been noted that attritional warfare would favor the state with more staying power, so a reasonable war aim of the Zhodani might be to attack and cause damage to 3 to 5 high population worlds and then negoiate a quick peace.

In Rebelion Book (MT) is stated that the Frontier Wars had no expasionist goals, but they were preventive wars to keep the Imperium from further expansion in the Zhodani (Core/Spinward) direction. I don't think they would really permanently occupy Imperial HiPop worlds.[/FONT]

We will soon see what MgT has to say about Zhodani which will give a flavour of the pre-FFW mood of the Zhodani. But, one thing that I always liked about the GT Alien Module for the Zhodani - it did not present them as a monolithic bloc. Like all humans, especially humans in a Democracy, like the Consulate is...there is bound to be disagreements and agreements and compromises.

So, I would agree that the Zhodani would have a good reason to moderate the War & Expansionist parties but they would always be a persistent voice - who is say some Noble commanding a Squadron does not want to go Rogue. His psi Officer could easily be manipulated into believing these are true orders.

I never liked the portrayal of the Joes as a surrogate Sov(iet)s rather the Consulate I figured was much like post-Tito Yugoslavia lots of clashing interests but presents itself to rest of the world as inherently stable with a growing division between Coreward & Trailing Quadrants. When the Empress Wave is detected, it begins to unravel parts of the social order and the Zhodani must figure out a way of getting the Imperium ready for the Wave which is the primary work of the Intelligence Officers within the Imperium setting up clandestine Psionic Institutes and create a mood within the populace to accept Democracy as opposed to Feudalism. So, they are practicing psychohistorians constantly monitoring the faultlines of the Imperium not upset the Balance of Power - but to ensure the long term viability and survival of the Zhodani race after the EW tears the Consulate apart.

Naturally, this is all known by only a select few in the top councils of the Consulate. What happens when these men and women of ambition are aligned by party-lines? Their actions may not appear rational. Add to that there is a still a Prole bureaucracy which does things by inertia rather than how the political structure operates...although, I would like to believe that Nobles extended Democracy through - Self Management.

 

[AndreaV]

Sorry if I'm coming in on this late...

One of the points overlooked with "defense in depth" is the problem the Roman Empire faced. Before the crisis of the third century the Romans had a "crust defense" strategy with the bulk of its forces spread out along the frontier. This worked well for quite some time, but eventually the strain of maintaining overwhelming force along the entire border became too great and the Empire went over to a defense in depth strategy. This worked well, at least for some time, but had one problem. Due to delays in communications, it would take some time for the mobile field armies to deploy to face an attack. This allowed the invader to penetrate the Empire and meant that the fighting took place on Imperial territory.

This exposed the frontier provinces to repeated warfare and even if the attack was thrown back, those provinces still suffered from being fought over. The Limitanei could deal with small scale raids, but faced with a major attack they fell back to fortified strong points, sent for the Comitatenses and waited. The result of this was that over time, the frontier provinces got devastated by having repeated wars fount over them.

I know this is a huge over simplification but it does illustrate the most significant problem with defense in depth. Namely that the fighting takes place relatively deep in your own territory.