The several reasons that Turkey has long been important for U.S. foreign policy, with a significant role in multiple issues, are still valid. It is one of the stronger states in its neighborhood, which is a tough neighborhood. It is a member of the North Atlantic alliance that sits astride the juncture of Europe and the Middle East—bordering, among others, Syria, Iraq, and Iran. It is the historical heir to an empire that once encompassed most of its surrounding region. It is a majority Muslim country, with what is usually described as a “mildly” Islamist government, that has been looked to as a worthy model of moderation and stability for nations to its south that have been beset with a shortage of both moderation and stability.
It thus matters when relations between Turkey and the United States hit rough patches, as has been the case lately. Things have gotten uglier in the past week, with Prime Minister Recep Erdogan evidently choosing to make the United States a diversionary scapegoat for domestic political troubles having to do with corruption cases involving members of his administration. Erdogan voiced vague warnings about meddling in the matter by “foreign ambassadors,” pro-government newspapers made more specific accusations against the U.S. ambassador in particular, and there were demonstrations outside the U.S. embassy. Presumably a basis for thinking the government's domestic audience might find such accusations plausible—besides the United States being a universal scapegoat for many things it has nothing to do with—is the U.S. residence of Fethullah Gulen, the Islamic cleric who was allied with Erdogan in the past but broke with him years ago and whose followers among the police and prosecutors are now seen as behind the corruption investigations.
The United States ought to approach its relations with Ankara today first with an acknowledgment (which would apply as well to its relations with other powers in the region) that Turkey will be partners on some matters but will have divergent views on others. Where views diverge, sometimes this will be for understandable and excusable reasons and it would be appropriate to agree to disagree. Erdogan's gambit of trying to use the United States to explain away his government's corruption problems is not one of those times. The United States does not need to raise the public temperature of relationship over this episode, but it certainly is right to stand tall in non-public exchanges and to make it clear it finds the gambit inexcusable.
U.S.-Turkish differences over the war in Syria, in which Ankara favors more active backing of armed rebels, fit more in the agree-to-disagree category. As a next-door neighbor that has directly felt on its own territory some of the effects of the war, Turkey deserves to have some slack cut in any judgment about its (not altogether consistent) responses to the conflict. But this would not make it any less of a mistake, as events in Syria have made increasingly apparent, for the United States to get more directly involved.
With still other issues on which Ankara and Washington disagree, including ones mentioned in Tim Arango's review of the bidding in the New York Times, Washington needs to look more at its own posture to explain why there is a disagreement at all. One such issue involves U.S. angst over Turkey signing oil deals with the Kurdish regional government in northern Iraq (rather than going through the central government in Baghdad). The Turkish approach is a more realistic response to the two-decades-old reality of Kurdish autonomy in northern Iraq than is adherence to a catechism of Iraqi unity. Turkey's current policy also represents a vast improvement over what was long its myopic and paranoic attitude toward Kurdish nationalism generally.
Another point of disagreement concerns Egypt, where Turkey strongly opposes the overthrow of the elected president, Mohamed Morsi. As the Egyptian military rulers demonstrate each week how far they are wrenching their country back from democracy and into arbitrary dictatorship (their most recent move being the bringing of implausibly imaginative criminal charges against Morsi), it is hard to see how Turkey is on the wrong side of this one. We have a tendency to see the posture of the Erdogan government as an Islamist thing; it is at least as much a democratic thing—and certainly is so in the eyes of the civilian government in Ankara, one of whose bigger accomplishments has been to tame the political impulses of the Turkish military, with its history of coups.
Then there is U.S. (and especially Congressional) pique over the suspected role of a state-owned Turkish bank in making purchases from Iran in defiance of U.S. sanctions. Chalk this up as one more instance of how the sanctions hurt U.S. interests by being a preoccupation and complication in U.S. diplomacy. To the extent this matter has become an additional irritant in the important relationship with Turkey, it has done more harm than any good that non-transactions by one Turkish bank possibly could do regarding the policies of an already heavily sanctioned Iran.