Conservatives invariably claim that any show of weakness emboldens aggressors and endangers peace. But just six years after Ronald Reagan failed to launch World War III over the Soviets downing a Korean airliner with 60 Americans onboard, the USSR collapsed. By 1991, the Soviet Union was gone. Maybe in his restraint, which looked disgraceful at the time, Reagan was acting wisely. Barack Obama has never done anything that could compare to Reagan's limp response to this wanton slaughter of innocents. But conservatives with short memories, writes Steve Chapman, nevertheless regard Obama as the most feeble, weak-kneed president since…well, since Jimmy Carter.