‘Not Losing’ Has Different Meanings for Iran and the U.S.

When an Irish Republican Army bomber came within a few feet of assassinating Margaret Thatcher in a hotel room in Brighton, England, in 1984, the terrorist group acknowledged the attempt with an official statement.“Today we were unlucky,” it said in a declaration addressed directly to the British prime minister. “But, remember, we only have to be lucky once. You have to be lucky every time.”Blood-chilling and callous as its language was (the bomb killed five members of the governing Conservative Party), the boast was a brutally accurate meditation on the nature of asymmetric warfare. In conflicts between two sides that...