Lyle J. Goldstein discusses the terrifying possibility of war between the U.S. and China. There are plenty of hawks in the U.S. government, he says, who might try to fight China were they to attack Taiwan or exert their influence elsewhere in the region. But even leaving aside the potential catastrophe of a nuclear war, Goldstein says American strategists don't give enough credence to the possibility that China could now defeat the U.S. even in a conventional war. The entire doctrine of trying to be the dominant military power in the world forever is foolish, wasteful and dangerous—instead,...