WASHINGTON -- U.S. President Barack Obama is set to meet with Turkish Prime Minister Tayyip Erdogan today at the White House in a meeting that's expected to raise hard questions about Turkey's alliances.
The two leaders meet amid differences between Washington and Ankara over Middle East policy, sanctions on Iran, and as the United States seeks to boost allied troop contributions for the Afghan war effort.
In Ankara last month, U.S. Assistant Secretary of State Phillip Gordon said the two leaders had "an awful lot of issues in the top ranks and then many more" to discuss during Erdogan's visit to Washington, listing among them Iran, Afghanistan, Iraq, the EU, Armenia, and Cyprus.
But hanging over the discussions will be the central question of whether Turkey has "switched its axis" -- as some commentators say it has -- away from the West; a concern felt in Brussels and Washington.
Evidence for that argument comes in part from Erdogan's recent statements that Iran is not pursuing a nuclear weapons agenda and Ankara's blossoming relationship with Tehran.
There was also a scheduled visit last month to Istanbul by Sudanese President Omar Al-Bashir, who has been indicted on charges of crimes against humanity by the International Criminal Court at The Hague.
'Robust And Broad'
Last week, State Department spokesman Ian Kelly hinted at the tension when he said that U.S.-Turkish relations were "very robust and broad."
"That's not to say that we don't have disagreements with Turkey. We have disagreements with all of our allies and we discuss them both privately and publicly. And we look forward to discussing the full range of our relations when Prime Minister Erdogan arrives," Kelly said.
In November, Erdogan visited Tehran to sign gas and trade deals and hosted the man he called his "good friend" -- Iranian President Mahmud Ahmadinejad -- at a summit of Islamic countries in Istanbul.
The Turkish prime minister also disappointed allies when he called sanctions imposed on Iran "arrogant" and said countries opposing its atomic program should give up their own nuclear arms.
From Washington's perspective, Turkey's warm relations with Iran made Tehran feel less isolated just as the West is trying to pressure the Islamic republic to accept a deal under which its uranium would be enriched abroad to mollify concerns that Iran may be seeking to develop nuclear weapons.
But in Ankara, the State Department's Gordon said "talk of a change of axis is a very significant exaggeration of what is going on in Turkey."
He admitted, however, that some of Erdogan's comments "do not reinforce the international consensus that [the United States is] trying to bring about."
Gordon added, "We're not surprised or worried by...Turkey's engagement and interest in the East.... I'm not saying that there aren't questions that are being asked, but I think that we are very confident that Turkey remains a close partner of ours, and a great friend and partners of the West and Europe."
Troops For Afghanistan
For his part, Obama, who visited Turkey in April, has said that Ankara can play a positive role in easing the dispute with Iran.
Despite the tensions over Tehran, Turkey remains a critical U.S. ally in many foreign-policy fronts, including with Pakistan, Iraq, the Middle East as a whole, and Afghanistan.
That's why analysts don't expect differences to dominate the meeting between Obama and Erdogan at the White House.
Turkey is a major transit route for U.S. troops and equipment destined for Iraq, and Turkey's Incirlik air base could play a key role as U.S. forces are drawn down.
The United States also relies on Turkey for cooperation in its fight against the PKK, which it considers a terrorist organization.
In Afghanistan, Turkey has some 1,750 troops in and around Kabul who are not engaged in combat operations and Ankara has long resisted pressure from Washington to offer more combat troops.
Obama has renewed his call to NATO allies to increase their troop commitments now that the United States is sending 30,000 additional American soldiers to war. And U.S. officials have said Washington is "expecting flexibility on the definition of the mission Turkish troops will undertake."
There is talk in some circles that Erdogan may try to strike a deal on the Afghan troop issue by asking the White House to help push peace talks between Greek and Turkish Cypriots. The two ethnic groups are deadlocked on the divided island nation of Cyprus, which is a member of the European Union.
The dispute has choked off Turkey's bid to join the EU and prevented closer cooperation between the Europe and NATO on Afghan operations.
The two leaders are also expected to discuss the prospect of restoring normalized relations between Turkey and Armenia, and its connection to the lack of progress on Nagorno-Karabakh -- the mountainous region which was the site of a bitter six-year war between Armenia and Azerbaijan.
Since 1994, Nagorno-Karabakh has enjoyed de facto independence but its Armenian-majority population and legal ties to Azerbaijan means its long-term fate is far from settled.
The State Department's Gordon said the White House is "strongly supportive" of the ratification of diplomatic ties between Turkey and Armenia, but acknowledged that the stalemate in Nagorno-Karabakh has dimmed that prospect.
with reporting from RFE/RL correspondent Brian Whitmore in Prague