Washington's ties with Ankara have improved significantly in recent years thanks to a personal relationship between President Obama and Turkish Prime Minister Recep Tayyip Erdogan. The two leaders have been in frequent contact, building a rapport that has translated into closer Turkish support for the U.S., including Ankara's 2011 decision to participate in NATO's crucial missile defense project.
Yet a crisis could be waiting in Syria.
Ankara and Washington both abhor the Syrian regime's brutal crackdown on demonstrators. But according to some reports, Ankara is hosting the Syrian opposition and possibly even helping arm it.
In contrast, Obama's cautious policy on Syria appears to be driven by a desire to avoid three things: the political unknown after Bashar al-Assad, war in an election year, and a new military campaign in a Muslim country.
Erdogan might find it increasingly difficult to tolerate Obama's "wait-and-see" strategy. For the Turks, slaughter in Syria is not an overseas affair, but rather a tragedy close to home that they cannot ignore.
Turkey's border with Syria spans 510 miles, crisscrossing ethnic groups and families. Some Turks have loved ones in Syria who are in harm's way. These constituents demand that Erdogan do his utmost to stop the al-Assad regime from perpetrating its crimes.
And many Sunni Turks, including those in the Ankara government, cannot turn a blind eye to the crackdown because they see the violence as a horrifying case of persecution by the Alawites who run the country.
Such religious sensitivities will be heightened later this summer during the Muslim holy month of Ramadan, which starts in late July.
When the Syrian uprising began, Ankara initially shied away from confronting Damascus, offering advice instead. But during last year's Ramadan, Turkish foreign minister Ahmet Davutoglu visited Damascus to ask al-Assad to halt his crackdown in recognition of that month's sanctity. Damascus ignored this request, instead sending tanks into Hama to attack civilians. Turkish-Syrian relations collapsed at this moment: Ankara switched to an aggressive posture against al-Assad, calling for action to force him to step down.
Even though Turkey has since backpedalled on some of its war rhetoric, Ankara could become more outspoken again this Ramadan. Moved by Muslim suffering during a holy month, Erdogan might make passionate calls for military action against al-Assad. This would throw a wrench in Ankara's relationship with Washington: the White House would have to choose between answering to Erdogan's passion and avoiding a military campaign in an election year.
There is one more reason why Ankara cannot live with the al-Assad regime, even if Washington can. Recent news reports suggest the Syrian regime is allowing the Kurdistan Workers Party (PKK), a Kurdish terrorist group that targets Turkey, to operate inside Syrian territory.
Turkey views the PKK as an existential threat, and it considers anyone who hosts the group to be an enemy. So even if Washington were to reach a modus vivendi with Damascus, it is hard for Ankara to ever become friends with al-Assad.
The longer Washington delays action against al-Assad, the more nervous Ankara will become about the PKK's growing strength inside Syria. Eventually, Erdogan will ask Obama to help him oust al-Assad and prevent the PKK from becoming a fighting machine next door. This divergence will test the limits of the Obama-Erdogan relationship.
For the time being, Erdogan might accept U.S. inaction, knowing that Obama's re-election chances depend on his ability to keep America out of an overseas conflict. But what happens after the U.S. elections in November?
Regardless of the winner, Erdogan will demand help from Washington to end the Syrian regime's patronage of the PKK. This is because Erdogan, like Obama, has election fever. The Turkish leader wants to become the country's first popularly elected president in polls to be held in 2013 or 2014. (Until a recent constitutional amendment, Turkish presidents were elected by the country's parliament.)
Should al-Assad continue to reign despite Erdogan's outspoken support for regime change, this will tarnish the Turkish leader's image as the tough guy who gets things done, the very image that has earned him respect and helped him win three successive elections since 2002.
He would also be weakened with the PKK thriving in Syria and using its territory as a springboard to launch attacks against Turkey. Then he would most certainly ask Obama to prove whether he is truly the friend that the Turkish leader thinks he is.
Soner Cagaptay is director of the Turkish Research Program at The Washington Institute.