The solution to the present problem of North Korea seems obvious–we should have invaded them a little more than a decade ago, just before they developed nuclear weapons. It looks like the modern version of the lesson of Munich: Britain and France should have opposed Hitler early, when he was still weak, instead of going along with the annexation of the Sudetenland. More generally, it is the argument for a foreign policy of figuring out early who are going to be your enemies and opposing them before they get strong enough to be dangerous.





That argument assumes that your nation not only will have an interventionist foreign policy, it will do it right. The U.S. has an interventionist foreign policy, as demonstrated in, among other places, Vietnam, Iraq and Afghanistan. It had one in 2006. It did not do anything serious to prevent North Korea from obtaining the ability to drop a nuclear weapon on the U.S. because the cost of invading North Korea would have been large and immediate, the cost of not doing it more than two elections away. The benefits of an interventionist foreign policy conducted by a government no more competent at it than ours is are much less than the Munich argument implies.





The costs are much greater. Modern U.S. history provides several striking examples, but I prefer a less familiar one.





A while back, rereading the first volume of Churchill's history of the Second World War, I discovered something interesting. The first time that Hitler attempted to annex Austria he was stopped not by France or Britain but by Italy. Mussolini announced that Italy would not tolerate a German annexation of Austria and made his point by moving Italian divisions into the Brenner pass. Hitler backed down.





What changed? When Italy invaded Abyssinia, England and France announced that that was a very wicked thing to do and took token actions against Italy for doing it. Mussolini concluded that Italy's World War One allies were not his friends and were not very dangerous enemies. The next time Hitler wanted to annex Austria, Mussolini raised no objection.





In Churchill's view, the correct response of the Allies to the Abyssinian invasion was either to forcibly prevent it or to ignore it. The first would have brought down Mussolini's government, the second would have retained him as an ally. Either a non-interventionist policy or a competent interventionist policy would have worked. The incompetent interventionist policy they actually followed gave Hitler his one significant ally.





What, in the absence of a time machine, can now be done about North Korea? The U.S. could, the President hints that it might, launch a full scale attack, probably nuclear as well as conventional. At this point that might not cost very many American civilian lives, since North Korea probably does not yet have the ability to deliver a nuclear weapon to the U.S. mainland, although it soon will. It would result in a very large number of civilian deaths in South Korea and possibly Japan. And in North Korea. It might happen, but I do not think it is likely to. Or should.





The alternative is to recognize that we are back in the world of mutually assured destruction, this time, fortunately, with a weaker opponent. Technological progress has made it possible for a relatively poor country to build intercontinental ballistic missiles with nuclear, perhaps thermonuclear, warheads. We are, however, enormously richer than North Korea--our GDP is more than six hundred times theirs--and considerably more advanced. The strategy that suggests is the one Reagan adopted for dealing with the Soviet Union, a competition in defensive weapons that they could not afford to win. I do not know enough about the current status of anti-missile technology to judge how workable that is, but I do not see any better alternatives.