The agreement this week between the governments of Iraq and Iran to enter a formal relationship to fight the Islamic State group should be deeply troubling to the United States. The Islamic State of Iraq and Syria, also known as ISIS, is a grave threat to the region and is responsible for the horrifying beheading of American journalists and an aid worker, as well as the brutal slaughter of countless innocent Muslims and Christians in Syria and Iraq. But as grave a threat as the Islamic State is, Iran is a much greater threat — especially if it acquires nuclear weapons.

In November, the U.S. decided to extend nuclear talks with the Iranians, despite stalling on the part of the mullahs. The practical effect of the decision is to give the Iranians more time to make a bomb.