When Secretary of State Hillary Clinton gets to Istanbul on Friday, senators and their staffs will be watching closely to see if she moves the ball forward on an agreement to station U.S. missile defense radar there, an agreement many Republicans oppose.

"We write with concern over recent reports that the administration may be nearing completion of a bilateral agreement with the Turkish Government to base a U.S. AN/TPY-2 (X-Band) radar in Turkey," wrote Sens. Jon Kyl (R-AZ) and Mark Kirk (R-IL) in a July 12 letter to Clinton and Defense Secretary Leon Panetta obtained by The Cable.

The senators want the radar to be based in either Georgia or Azerbaijan, which they argue are better locations for defending against a missile attack from Iran. But more broadly, they are concerned that Ankara will place a number of onerous restrictions on the radar, such as demanding that no data be shared with Israel. The senators have also accused Turkey of violating U.S. sanctions against Iran, which they said calls into question their reliability as a partner in organizing a missile defense system aimed at Tehran.

In a May 12 meeting with Principal Deputy Under Secretary of Defense for Policy James Miller, a senior Missile Defense Agency representative told the senators that "a forward-deployed X-Band radar in either Georgia or Armenia would have significant advantages for the missile defense of the United States," the senator wrote.

The senators wrote a May 16 letter to Miller asking for a complete analysis of alternative sites, but they said that they have yet to receive any response.

Kyl and Kirk also suggested that they will attempt to thwart any missile defense agreement with Turkey unless the Turks agree to share data with Israel, stop violating Iran sanctions laws, and keep the system under the control of U.S. personnel.

For both the Obama administration and the George W. Bush administration preceding it, international missile defense deployment has always been based on both security and diplomatic considerations. The Bush administration plan to place missile defense infrastructure in Poland and the Czech Republic was a key aspect of strengthening relationships with those two countries, until the Obama administration scuttled it.

A senior GOP Senate aide explained the insider rationale to The Cable.

"Secretary Clinton knows the Congress well and she knows that support for a radar in Turkey will quickly collapse on both sides of the aisle if the Turks get any control over its operational activity or veto rights over sharing data with Israel," the aide said. "Given Turkey's strained relationship with Israel and non-compliance with U.S. sanctions against Iran, there's a strong feeling that if the Turks have any operational control over the radar we can be sure it will be turned off the day we need it most."