Thanks to the Iraqi military's chaotic flight from Mosul in June, jihadists from the Islamic State are now armed with abandoned U.S. weapons and armored vehicles. Iraq's Kurds -- arguably the most reliable U.S. allies in the Middle East after Israel and Turkey -- are not.
The implications of this bizarre mismatch between U.S. arms and interests has become clear in recent days as Islamic State militants have driven Kurdish Peshmerga fighters from several towns near Mosul in northern Iraq. The Sunni extremists acquired two oil fields, and they are fighting to seize a dam that supplies water and electricity to much of Iraq. Tens of thousands of residents of the Yazidi religious minority have fled for their lives.