If politics ain't beanbag, as Mr. Dooley had it, defense politics, happily, ain't all pork barrel, as this young political scientist carefully argues. To be sure, contractors do spread subcontracts as widely as possible, and members of Congress do defend programs in their own districts. But these stratagems have little real impact either on how much is spent or which systems are bought. Then why all the fuss? In part because defense procurement is so visible (accounting for two-thirds of the government's discretionary spending), claiming credit is good for congressional winners and crying "pork" good for the losers. In the end decisions are political-that is, about values-not merely technical. Based on the parlous history of the A-10 aircraft, Mayer observes, "if the Pentagon is not always right when it wants to buy something, it is not always right when it wants not to buy something."