Si vis pacem, para bellum


"If you wish for peace, prepare for war"

The embodiment of deterrence - almost everyone in the Western world has heard this at least once.

It's a one-sided advice; it doesn't consider foreign reactions and it doesn't provide guidance about the extent of advisable preparations.

The whole deterrence thinking and the use of this saying have thus become too extreme.
Some U.S.Americans don't feel safe unless their single nation spends more on the military than all other nations (allied, friendly, neutral and hostile) together.
Well, even then some can feel "threatened" and call for more, more, more.

This is - obviously - not my behaviour. I don't call for magic numbers (like 4 % of GDP) as preparation for war; the challenge is too complex to be mastered with rules of thumb only.
We can break our economy and thus our wealth and long-term security by overspending on "defense".

"si vis pacem, para bellum" has gone wrong many times in history by spending too much, too little or for the wrong capabilities.

An example of spending too much (leading to collapse) is the permanent war economy of the Soviet Union, a remarkable feat of their despised planning economy. They prepared for war to survive (by keeping peace; yes, they weren't as bad as depicted during the Cold War and we weren't as good), but neither managed to invest enough into their economy nor did they allocate enough resources for civilian consumption to keep the people content and corruption covered up.

Another example of spending too much was probably the arms race among European armies in 1912-1914 that led to war instead of keeping peace - the result was not triumphant victory, but broken societies.

An example of spending too little was certainly the failure of UK and France to react timely to the German military buildup of 1933-1939. They only became serious in 1937, and gave up their hopes for peace as late as early 1939.

Finally an example for wrong allocation of resources; the German Hochseeflotte (high seas fleet), a battleship-centric navy meant to deter the UK from entering war with Germany ("Risikoflotte"; risk fleet).

The British were able to focus on shipbuilding, while the Germans with their larger economy were not able to do so - they faced the second- and third-strongest armies of Europe (French and Russian) as hostile neighbours.
Admiral Tirpitz' calculation that the British would not dare to enter a war if Germany's fleet was 2/3 as strong as the Royal Navy was a too static thought. The British were uncomfortable with any ratio that was even close to that and a naval arms race yielded huge fleets at very high cost, but the large and expensive German fleet didn't prevent the British from joining the First World War at all.
Most resources for the navy were wasted, Germany presented itself as hostile to the British, manpower/expertise/budget were tied to the navy instead of the army (which had quite lacking funding and wasn't able to fully cope with the French army's buildup until 1912). In the end, most navy resources were mis-allocated; the German army could have been much more powerful and decisive in 1914 - at lower overall defence expenditures pre-1914.

The last example also shows how complex deterrence really is and how important it is to include possible and anticipated reactions into your strategic decision making.

"Si vis pacem, para bellum" has a huge conceptual problem; it doesn't work for all at once apparently. The principle could work for all nations at once if an inferior, but strong enough military had enough deterrence effect. Historical evidence contradicts such an assumption. The risk fleet strategy failed in 1914 and the British/French armies and air forces were equally large as Germany's in 1939/40, still failing to prevent both WW2 and the French campaign of 1940.

Game theory can be used to show this conceptual weakness; "Si vis pacem, para bellum" leads to arms races, not relaxation of tensions in situations of crisis. Every power seeks superiority in order to prepare well enough - but its moves are being countered by the hostile power's preparations.
A strategy of superior readiness (or even "dominance" or "primacy") can hardly succeed for both blocs.

Those powers who fail to be strong enough to deter war can only hope for the niceness of the superior power - or rest on third parties for their security.

Other measures promise better results than an arms race;
arms control treaties, an emphasis on defensive military capabilities, diplomatic solution of conflicts and the creation of geo-strategic buffers, for example.

A proper reaction to a military power buildup somewhere in the world is not to enter an arms race no matter what. Instead, we have to consider many factors; including the suspected intent, the relevance for our security (at our homes), the quality of our relations to that foreign power and our ability to improve the relations to avert war and the military might of our allies.

Finally a note about the peace movement; pacifism is not outright idiotic, but a rather nice idea. Its major weakness is the lack of an alternative to deterrence.
Deterrence in its many forms is still the primary means of securing peace even in face of dangerous people in power. Sometimes it works, sometimes it fails - it's being considered as indispensable by major powers.
Maybe they'll sometime invent such an alternative, or we'll sometime succeed in turning deterrence global (U.N. responding to aggressions instead of mere national/alliance self-defence) to get rid of war.

"Si vis pacem, para bellum" has been exaggerated and mis-used by warmongers in my opinion. It's a simple saying that covers only a small aspect of reality. Its wrong application could hurt us badly.
The protection of peace is a delicate affair that requires a lot of thought and doesn't suit itself well to simple answers.

Sven Ortmann

Another reading about deterrence, otherwise unrelated:
"Military Parades Demonstrate Chinese Concept of Deterrence"


  1. I think your example of the German high seas fleet is well picked when transfered especially to modern European naval strategy. Altough we are far from an arms race in that matter but short in resources (this is a often heared bromide I know that) the final outcome seems to me quite same: Aside from some exceptions (particularly UK and France who have a vital interest in sea control) the most European countries like Germany cannot afford and at least in my opinion do not require a signifacant naval power. Considering an increased coordination of military capabilities in Europe I'd like to ask what you think of the much maligned concept of Jeune Ecole for smaller coastal states to effectively respond to those problems and simultaneously build up a sufficient naval deterrence?

  2. Sven what you said is right, but 'Si vis pacem, para bellum' is also right if used in the correct context - it is on the gate at many of britains officer training bases; in this context is right, you have to prepare the personell to be able to fight after all equipment is a lot easier to build than it is to train the personel.

    yours sincerly


  3. @Norman:

    The European powers have the economic reserves to build up greater naval power, but it would be wasteful to do it.

  4. Peace? Nations go to war for the dumbest of reasons. Or even due to the interests of a minor few within a state...

    Peace movements will take FOREVER (not in our lifetimes) to achieve their imagined utopias. Respect amongst peoples of different skin tones & creeds a rarity even in this Age of Information. (The EU is a miracle!)

  5. Thank you for the link. As usual very instructive. Only to get it right: do you mean that all European powers should quit their military shipbuilding programs? Isn't it neccessary to specify the military capabilities and needs of each member of the EU depending on their geographical or ecnomical situation? Take the UK as an example who wouldn't primarily be threatend by an land attack due to her island position. As a consequence should Britain not rather maintain a convincing fleet than invest in major ground forces?

  6. Extremely small and extremely large services don't work well.
    It's advisable to have some diversity and a mix of forces (that communicate well with each other).
    It's not necessary to have an air force and a submarine force in a country like Croatia, though.
    Existing competencies also play into this, as do politics, of course.

    It's not obligatory to optimize the defence of Europe, but we should be clear that our forces are meant for defence - not a wasteful arsenal for great power games.

    The British and French are still quite much into wasteful great power thinking and countries like Germany, Spain, Italy and Netherlands are drifting towards that as well (especially the navies, as evidenced by amphibious aircraft carriers and LPDs).

  7. The example of the High Seas Fleet is overdone. While the question of whether this fleet should have been built is a valid on, the High Seas Fleet was actually quite successful in WW1. It required the British to expend substantially greater resources maintaining the Grand Fleet at a high state of readiness throughout the war, while the HSF could swing at anchor acting and just look threatening. Had the HSF not existed, those resources would have been available for the Western Front where they would have done much more damage to the German war effort than was otherwise the case. This was a war of attrition, and any force that requires the enemy to expend more resources than you do is a worthwhile investment.

  8. The navy's pre-war budget moved to the army would have boosted German land power to a war-winning level. Reserve manpower to do that was available in the navy and among the conscripts.

    The key is that the British weren't inclined to build a huge army before the war - even if not challenged at sea.
    They weren't even sure about whether to send a BEF to France before the war. They didn't turn to conscription before 1916.

    The navies took resources away from the armies in all major participants, but the critical lever is that the British would have maintained a huge fleet anyway. Look at the 1890's pre-dreadnought production before the German-British naval arms race - the British were building many capital ships even without being challenged. Their army was a pretty much a colonial army till 1914 and even during the Napoleonic wars they had no really big army on the continent.

    The Germans could have exploited this setting, but mis-allocated their resources.


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