Israel's Proportionate Response

By Michael Gerson

WASHINGTON -- There is no question -- none -- that Israel's attack on Hamas in Gaza is justified. No nation can tolerate a portion of its people living in the conditions of the London Blitz -- listening for sirens, sleeping in bomb shelters and separated from death only by the randomness of a Qassam missile's flight. And no group aspiring to nationhood, such as Hamas, can be exempt from the rules of sovereignty, morality and civilization, which, at the very least, forbid routine murder attempts against your neighbors.

Israel's response has been criticized as "disproportionate," which betrays a misunderstanding of proportion's meaning. The goal of military action, when....