Overnight Defense: White House, GOP clash over Iran letter

THE TOPLINE: The White House and Democrats blasted Senate Republicans for an open letter to Iran's leaders, saying it undermined President Obama's efforts to negotiate a nuclear deal. The letter, signed by 47 Senate Republicans, warned Iran that the next occupant of the Oval Office could scrap a nuclear deal "with the stroke of a pen." "Anything not approved by Congress is a mere executive agreement," they wrote. "The next president could revoke such an executive agreement with the stroke of a pen and future Congresses could modify the terms of the agreement at any time." Obama accused Republicans of making "common cause" with factions in Iran that are determined to thwart diplomacy. "I think it's somewhat ironic to see some members of Congress wanting to make common cause with the hardliners in Iran," Obama said. Congressional Democrats joined the White House in denouncing the letter, with Sen. Dick Durbin (D-Ill.) calling it "a cynical effort by Republican Senators to undermine sensitive international negotiations -- it weakens America's hand and highlights our political divisions to the rest of the world." "Understand that if these negotiations fail, a military response to Iran developing their nuclear capability becomes more likely," added Durbin, the second-ranking Senate Democrat. Sen. Barbara Boxer (D-Calif.), a member of the Senate Foreign Relations Committee, accused Republicans of trying to "sabotage" the nuclear talks, calling the letter a "desperate ploy" to prevent an agreement. Senate Minority Leader Harry Reid (D-Nev.) assailed Republicans on the Senate floor as "undermining our commander in chief while empowering the ayatollahs." "Republicans need to find a way to get over their animosity of President Obama," Reid said. The letter comes as the administration is just weeks away from the March 24 deadline for negotiators to reach a framework agreement. BENGHAZI CHAIR DROPS OUT OF FUNDRAISER. The chairman of the House Select Committee on Benghazi won't attend a Virginia GOP fundraiser after learning that the event would highlight his role in the ongoing investigation. A National Review report on Monday said Gowdy would appear at a March 19 fundraiser titled "Beyond Benghazi," featuring a film screening and an interview with the South Carolina lawmaker. "The chairman was unaware that organizers of this event intended to feature or even mention Benghazi. He has not raised money using Benghazi, and will not speak about Benghazi at fundraising events. Having been made aware of this group's plan, he no longer will be participating in the event," panel spokesman Jamal Ware said in a statement. Earlier on Monday, Rep. Elijah Cummings (Md.), the panel's top Democrat, said the panel had "given up any pretense of a legitimate investigation." "From issuing a completely unnecessary subpoena to Secretary Clinton to Republican fundraising off of the tragedy in Benghazi, it appears that the Select Committee has given up any pretense of a legitimate investigation, and now has just become a surrogate for the Republican National Committee," he said in a statement. "This taxpayer-funded committee should focus on an investigation that ensures reforms are implemented to improve the safety and security of our officials serving overseas," Cummings added. UKRAINE POLICY IN THE SPOTLIGHT: Lawmakers from both parties on the Senate Foreign Relations Committee are set to grill administration officials  Tuesday about the president's reluctance to give lethal weapons to Ukraine. Officials from Defense, State and the Treasury department will testify at the hearing. Members in both chambers have repeatedly called for the White House to get tougher on pro-Russian rebels who are fighting Ukraine's government. But the White House has refused to give lethal arms to Kiev's forces, arguing that the move could further prove Russia. Obama and European allies have chosen to impose multiple rounds of sanctions on Russia. Several senior administration officials in recent weeks, though, have suggested the White House may change course, as violence intensifies. "I think we should absolutely consider providing lethal aid," Joint Chiefs of Staff Chairman Gen. Martin Dempsey told a panel of House members last week. NO MORE A-10 RETIREMENTS? This year's annual defense policy bill will reverse an Air Force plan to shift A-10 attack aircraft toward retirement by giving them backup[ status, according to Senate Armed Services Committee Chairman John McCain (R-Ariz.). "We will be working hard and most likely reverse that decision in the defense authorization bill," Sen. John McCain (R-Ariz.) said Friday, according to theArizona Daily Star. He knocked the plan as a "compromise that was made last year in response to the Air Force's misguided attempt to retire all the A-10s." Lawmakers in both chambers rejected a proposal to mothball the entire "Warthog" fleet when they drafted their annual defense policy bill last year. But they did allow the service to move up to 36 of the service's nearly 300 attack jets into so-called inventory status, pending a review by the Pentagon and the Defense secretary. The service began implementing its plan last month, shifting 18 attack jets into backup status, including nine from Davis-Monthan Air Force Base in Arizona. "It's not a huge deal in terms of the number of A-10s there at Davis-Monthan -- just standing down nine (planes) into non-maintenance status is not what we wanted, but it certainly is a small item as compared to the desire to retire all of them," McCain said. "We've made it clear to the Air Force that we will not authorize further reductions in the A-10's status until such time as the Air Force has an adequate replacement for the A-10, which they do not have," he added. "I can assure you, it's a very high priority for the committee." Rep. Martha McSally (R-Ariz.), who has chided the Air Force's moves at Davis-Monthan, told the newspaper that she was "frustrated because these were compromises agreed to before I got into office." McSally, a retired Air Force colonel and A-10 fighter pilot who now sits on the House Armed Services Committee, said lawmakers "have limited options to stop" the service's plan. "But I do want to provide tight oversight to the process," she said. IN CASE YOU MISSED IT:  -- Bill would require study of VA's burial practices -- Senator: US must not play ISIS's game by deploying troops -- Former senators urge Iran vote with explosive ad -- Bipartisan bill would expand VA Agent Orange coverage -- House, Senate panels to hold joint hearing at VA 'Candy Land' Please send tips and comments to Kristina Wong, kwong@thehill.com, and Martin Matishak, mmatishak@thehill.com. Follow us on Twitter: @thehill, @kristina_wong, @martinmatishak