Yes, say Paul Collier and Bjorn Lomborg:
A new study for the Copenhagen Consensus project that includes the first ever cost-benefit analysis of United Nations peacekeeping initiatives concludes that military might is an important tool for reducing bloodshed around the world.
Iraq is a misleading guide to the effectiveness of such initiatives. Unlike the vast majority of conflicts, its civil war was sparked by an international war. The far more typical scenario is political violence within a small, low-income, low-growth nation burdened with strong ethnic divisions.
Military intervention wont be the answer in every hot spot; nor should it be the developed world's only response. Post-conflict aid designed to prevent violence from recurring is much more politically acceptable than the use of force, although it is very expensive.
The Copenhagen Consensus study recommends that aid to post-conflict countries be tied to limits on military spending. Placing conditions on aid packages is controversial, but about 11 percent of all aid is currently diverted into military spending, which significantly increases the likelihood of violence. The lower risk of conflict and better use of that money would mean the benefits from aid climb to 4.5 times higher than the costs.
The first cost-benefit analysis of peacekeeping initiatives reveals that the risk of future conflict depends upon the scale of military deployment. Compared with no deployment, spending $100 million on a peacekeeping initiative reduces the 10-year risk of conflict from around 38 percent to 16.5 percent. At $200 million per year, the risk falls further, to around 12.8 percent. At $500 million, it goes down to 9 percent, and at $850 million drops to 7.3 percent.
Because of war's massive costs, each percentage point of risk reduction is worth around $2.5 billion to the world. The most expensive deployment reduces the risk of conflict by a massive 30 percentage points, with 10-year gains of $75 billion, compared to the overall cost of $8.5 billion. This is a very promising investment.