Many countries have nuclear weapons, and many more want them. Only one, though, has its neighbors and the world terrified. That country is Iran. Why is everyone so concerned? Because the Islamic theocracy has repeatedly threatened to destroy Israel, sponsors global terrorism, and would leverage the deterrence effect of a nuclear weapon to advance their anti-Western and anti-American interests. Bret Stephens, foreign affairs columnist for the Wall Street Journal explains the one thing you really need to know in order to understand why we can't let Iran get the bomb -- they may actually use it.