Tomorrow is an ignominious anniversary. On that date in 1961, about 1,400 American-trained Cuban exiles launched a secret invasion of Cuba in an effort to overthrow the Fidel Castro regime. After landing on the island’s southern coast at the Bay of Pigs, the invading guerrillas were routed by government forces. The humiliating disaster gave rise to a rare, publicly available Justice Department analysis of presidential power to wage covert war.