The gravest danger: the president who invaded Iraq citing fear of nuclear blackmail has been cavalier about preventing it elsewhere.

WHEN ASKED IN THE FIRST PRESIDENTIAL Debate of 2004 what constitutes the "single most serious threat to American national security," there was a brief instant of agreement between President Bush and Senator Kerry. Both answered, "Nuclear terrorism." The president repeated that he agreed with his opponent that the biggest threat facing the country is nuclear weapons "in the hands of a terrorist enemy."

To prevent a nuclear terrorist attack on an American city, the administration accomplished a great deal more in its first term than the critics ...