Kevin Williamson of National Review Online wants to put data and research to work in fighting society’s largest public policy problems.

One of the most interesting projects of recent years is the Copenhagen Consensus, the Bjørn Lomborg–led project to apply welfare economics to deep-seated global problems, inviting economists and issue scholars to do some rigorous number-crunching and come up with some projects to maximize the bang/buck ratio. The recommendations have been surprisingly unsexy: micronutrient-supplement programs, bigger and better-structured subsidies for malaria prevention (those damned mosquitos, again), immunization, the spread of better agricultural practices, water projects.

Straight-up policy questions, notably barriers to trade, also are on the radar. While foreign aid accounts for only a tiny share of U.S. government spending, in absolute dollars the sums are considerable. It is spent better than you might expect: Thanks in no small part to President George W. Bush, the United States has made large investments in HIV prevention, especially in Africa, which actually seems to do some good. A great deal of money is spent on infrastructure projects and capacity-building for foreign states such as Afghanistan, which, even with the inevitable graft and waste, is probably the right approach.

What’s needed is a similar approach to domestic questions, and to a few foreign-relations questions closer to home. It’s a hard sell when a non-trivial share of the population has adopted “Eek! A Mexican!” as the main principle governing relations with our southern neighbor, but it is inarguable that the United States would be much, much better off if Mexico were a lot more like Canada and a lot less like Venezuela (Mexico is only two steps ahead of the late Boss Hugo’s socialist heap on the GDP/capita rankings) and if it had stronger institutions that were more capable of dealing with things like drug cartels and internal economic refugees. But who is going to help Mexico build that capacity? Guatemala?

In a sane world, U.S. political debate would be less about how rich men live in Greenwich and San Mateo Park and more about how the schools are run in Cleveland and Philadelphia, and we’d acknowledge that Mohammed al-Kaboom isn’t going to kill nearly as many Americans this year — or any year — as diabetes and prescription-drug addiction. We’d acknowledge that what is hurting the U.S. economy is mainly decisions made in Washington (and, Albany, Sacramento, Columbus, Lansing . . . ) and not schemes hatched in Beijing or Mexico City. The headlines would be about mosquitos, not about sharks. This isn’t a call for post-ideological “pragmatism,” which is almost always just 20th-century progressivism dressed up with a few dodgy charts, but rather for a genuine effort at discerning what actually can be done, at what cost, and establishing priorities among those things.