I’ve been meaning to write a quick post about the question of when a nation should go to war, and when it should not — and in particular, under what conditions the United States should use large-scale military force against another country. I don’t mean the question of whether a war is legal under the international humanitarian law governing jus ad bellum. I mean the question of when large-scale military engagement is a good idea, something that the public should support. It’s not inconceivable that there are situations when military force is a good idea even though the legal basis is unclear or lacking — such as Kosovo in 1999, or maybe Libya in 2011 — and there are also, certainly, situations when the legal grounds for a war exist, but going to war would be unwise — such as attacking Russia in response to its annexation of Crimea last year.
Based on the armed conflicts involving the United States during my lifetime, it sometimes seems as though the wisdom of entering or not entering an armed conflict gets determined in retrospect, based on how the war turned out — which doesn’t seem like a useful or fair standard for judging wisdom. No one seems particularly bothered about Desert Storm, looking back, although many progressives at the time (including, for example, Joe Biden) opposed military intervention. On the other hand, many people seem to feel that the United States should have intervened in Rwanda to stop the genocide, although there was no great progressive push to do so at the time. It’s hard to avoid the conclusion, looking at attitudes toward U.S. uses of force over the last few decades, that we tend to treat decisions about wars as good decisions when they turn out well, and treat them as bad decisions when they don’t. But we often can’t know in advance how a war, or the choice not to go to war, will turn out — wars are notoriously unpredictable, and often develop their own momentum, and motivations and expectations frequently change — so how are we supposed to decide what to support beforehand?
The idea I’ve been meaning to post is an answer to this question. It’s a fairly simple one, and it may already appear somewhere in the literature on just war. But I’ve never come across it before.