President Bush has asked the military to shoot down a spy satellite that’s supposed to crash into Earth next month. Disarmament guru Michael Krepon seems upset: ”In the history of the space age, there has not been a single human being who has been harmed by man-made objects falling from space.” That may be true. It may also be true that we don’t want the satellite to come down in the hinterlands of Siberia, where parts of it might be retrieved by people who shouldn’t have it. But the odds of a genuine calamity–such as the satellite hitting Tokyo or Denver–are not zero.

Let’s remember that ICBMs are man-made objects that fall from space, and they’re designed specifically to hurt people. The reason we even have the option to protect ourselves from a crashing satellite boils down to two words: Missile defense. Better to have it and not need it than need it and not have it. We ought to have more of it, but let’s hope that for present purposes we have enough.