A group of U.S. senators, including Arizona’s John McCain, is crafting a plan to save the A-10 close air-support jet — a mainstay of Tucson’s Davis-Monthan Air Force Base.

The fate of the A-10 “Warthog” is still uncertain amid an Air Force plan to retire the entire fleet, but its future will likely come into sharper focus this week as the defense budget fight resumes in both houses of Congress.

On May 7, the House Armed Services Committee adopted an amendment to the National Defense Authorization Act, sponsored by U.S. Rep. Ron Barber, a Tucson Democrat, that would fund the A-10 fleet through fiscal 2015 by shifting money from the Pentagon’s overseas war budget.

That amendment may not survive in the Senate, but members of the Senate Armed Services Committee are expected to propose an alternative plan to save the A-10 when it writes its own version of the bill this week.

In advance of the committee’s consideration of the bill on Wednesday, key senators, including McCain, a Phoenix Republican, ramped up their support of the A-10. The House is expected to bring up its version of the bill for floor debate on Wednesday and vote on it on Friday.

In a press conference last week, McCain reiterated his support for the A-10 as the nation’s best close air-support platform.

“Obviously, if we did away with the A-10 capability it would reduce dramatically the ability of the United States Army and Marine Corps from receiving what is a critical element in the battlefield equation,” he said.

While acknowledging the A-10’s status as the nation’s best platform for close air support of ground troops, Air Force officials have said that, because of the need for deep budget cuts, the service can’t afford to keep the “single-mission” plane.

Winslow Wheeler, a former Pentagon budget official and director of the Straus Military Reform Project, said he doesn’t expect the House to reverse Barber’s amendment, which would fund A-10 operations for a year with money from the overseas war budget. But Wheeler and some lawmakers have criticized that shift from the so-called Overseas Contingency Operations budget, since it is not part of the main Pentagon budget.

To save the A-10, Wheeler and other analysts say Senate backers will likely have to find a new “payfor” — or budget offset — for it.

At last week’s news conference with McCain, New Hampshire Republican Sen. Kelly Ayotte said members of the Senate Armed Services Committee, including the chairman, Sen. Carl Levin, D-Mich., are working on plans to save the A-10, the Air Force Times reported. Last week, Levin said he supports keeping the A-10, but that using overseas war funding is not a legitimate budget offset.

“I am working with Levin to come up with a payfor that does not use OCO (Overseas Contingency Operations funding) but stays within budget caps,” Ayotte said, according to the Air Force Times.

Ayotte — whose husband is a former A-10 pilot — has led the charge to save the Warthog and is leading negotiations with Levin for a possible alternative budget offset.

McCain’s involvement in the effort is key, Wheeler said.

“The fact that he’s joining with her is a pretty good indication that they’re going to put together something that’s going to pass the Senate, but we don’t know what.”

Barber’s ability to get his amendment approved by the House Armed Service Committee by more than a 2-1 vote margin — despite its dubious funding offset and opposition from the committee’s chairman — is a testament to the strong bipartisan support the Warthog enjoys, Wheeler said.

In approving Barber’s measure, the committee rejected a proposal by committee Chairman Howard “Buck” McKeon, R-Calif., that simply required the A-10s be stored in a way that would make it easy for them to be returned to combat as quickly as possible.

“It’s very clear that the A-10 community has made itself extremely powerful,” Wheeler said. “Those guys are all over the Hill talking to people, and, most importantly, they made clear the argument why the A-10 is such a spectacular performer — it’s much more than just a pork issue.”

Even after each chamber passes its own version of the defense authorization bill, a House-Senate conference committee will craft the final version.