Iraq's acquiescence in possibly allowing Iranian weapons deliveries to the Syrian regime demonstrates Washington's limited influence in postwar Iraq, its inability to halt Syria's 18-month conflict and its continued struggle against Tehran for supremacy in the region.
U.S. officials said Wednesday that Iraq had shut down the movement of Iranian aid to the regime of Syrian President Bashar Assad earlier this year, but that suspected arms deliveries resumed in July. And three U.S. senators warned Baghdad that it risked damaging relations with the U.S. if it is allowing Iran to use Iraqi airspace to deliver weapons to Syria.
The officials spoke on condition of anonymity because they weren't authorized to discuss the information publicly.
Iraq's government said Iran had assured it that the flights to Syria were delivering only humanitarian aid, and challenged the U.S. to prove otherwise.
It was the latest example of Baghdad's warming relations with Tehran and weakening ties with Washington, after a decade in which the U.S. spent hundreds of billions of dollars and lost almost 4,500 lives after the 2003 invasion that toppled Saddam Hussein's dictatorship and tried to stabilize the country.
"The Iranians have been so explicit, so clear about their unyielding support for the murderous Assad regime," State Department spokesman Patrick Ventrell said. "All of this destructive assistance should stop, whether it's materiel, whether it's direct training and assistance to help stage manage the repression."
Ventrell declined to delve into the details of diplomatic discussions, but the U.S. official said the issue of Iranian weapons transfers to Assad's forces has been a bone of contention for several months, with American intelligence noting a significant increase in the number of flights over Iraq as the Syrian regime has gotten more desperate.
The resumed flights were first reported by The New York Times.
White House spokesman Tommy Vietor said Iraq has taken steps in the past to meet its U.N. Security Council obligations to prevent Iran from exporting weapons. "It must continue to do so," he said in an email.
On a visit to Baghdad, Sen. Joe Lieberman, I-Conn., was far blunter, calling into question the long-term partnership Iraq and the United States agreed to in 2008.
"This kind of problem with these Iranian overflights can make it more difficult to proceed with the Strategic Framework Agreement in the manner that the prime minister and we would like to see happen," Lieberman told reporters in Baghdad. "So I hope this is cleared up quickly."
Sen. Lindsey Graham, R-S.C., blamed the Obama administration for letting U.S. influence in the Middle East slip. Sen. John McCain, R-Ariz., also was on the trip.
"This region is about to explode," Graham said. Iraqi leaders, he added, are "probably not pushing back on Iran … because they don't see how this ends. There's an amazing lack of American leadership, and it's beginning to show on all fronts."
The issue of the overflights reflects a trifecta of worries for the United States. Iraq is a fragile democracy sandwiched by long-time Shiite allies Iran and Syria, a country in the midst of a brutal civil war that has now killed at least 23,000 people, according to activists.
The Obama administration has been touting Syrian rebel advances in recent weeks, insisting that the tide of the war is turning against Assad. But Iranian support for Assad is one of the factors that could greatly prolong the conflict, especially as the U.S. and other Western powers insist on staying out of the conflict militarily and not providing weapons to the anti-Assad opposition.
Responding to the U.S. accusations, Ali al-Moussawi, media adviser to Iraqi Prime Minister Nouri al-Maliki, confirmed that Iranian planes are flying over Iraq to deliver goods to Syria. But he said Tehran assured al-Maliki the flights are carrying only food and humanitarian aid to help war victims.
Al-Moussawi said Vice President Joe Biden promised to send al-Maliki evidence that the flights are ferrying weapons. But proof never arrived, he said.
"The Iranian government has said that it respects our decisions," al-Moussawi told The Associated Press. "Until now, there is no evidence of any violation in this regard, and if anyone has any evidence they should bring it to us and we will take the needed measures."
U.S. officials confirmed that Biden brought up the issue in a conversation with Iraq's leader two weeks ago, but wouldn't speak about any evidence that may have been provided.
Ventrell said the easiest solution was for Iraq to require Iranian aircraft "to land and to be inspected in Iraqi territory."
Yet it's unclear how Iraq would enforce that rule, with an air force that has few planes and no fighter jets to protect its skies. That mission was previously handled by the U.S. military before American troops withdrew from Iraq last year.
While Iran may be sending the weapons as part of a region-wide battle for influence with the United States, the passivity of Iraq's Shiite leaders may reflect more parochial concerns and the history of decades of minority Baathist domination, said Aram Nerguizian, a Middle East specialist at the Center for Strategic and International Studies.
He said it made sense that Iraq was hedging its bets at a time of dwindling hopes for Syrian peace and the possibility of another hostile Sunni state emerging one day on its borders.
"It's not just about helping Iran," Nerguizian said. "This is also a byproduct of an Iraqi political environment where the leaders are far more worried about threats to Shiite rule."