Harder to get around is the reality of a Turkish government that is a member of NATO but long ago stopped acting like an ally of the U.S. or a friend of the West. Former U.S. Ambassador to Turkey Francis Ricciardone declared this week that the Turkish government “frankly worked” with the al-Nusrah Front—the al Qaeda affiliate in Syria—along with other terrorist groups. Ankara also looked the other way as foreign jihadis used Turkey as a transit point on their way to Syria and Iraq. Mr. Ricciardone came close to being declared persona non grata by Prime Minister Recep Tayyip Erdogan’s government last December.

This history—along with the Erdogan government’s long record of support for Hamas in Gaza and the Muslim Brotherhood in Egypt—explains why the excuses now being made for Turkey’s nonfeasance ring hollow. ISIS has taken Turkish diplomats and their family members hostage in Mosul inside Iraq, but Turkey is not the only country whose citizens have been taken hostage. Ankara also fears that arms sent to ISIS opponents may wind up in the hands of the PKK, the Kurdish terrorist group. But that doesn’t justify shutting down Incirlik for a U.S. operation.

The unavoidable conclusion is that the U.S. needs to find a better regional ally to fight ISIS. True to type, Arab states such as Saudi Arabia are proving to be reluctant partners, at least in public, and it’s unclear how much the new government in Baghdad can contribute before its army regroups.