WASHINGTON — A defense authorization bill now on the Senate floor would maintain a freeze on Air Force mission shifts that would otherwise spell the end for A-10 fighters in Fort Smith, U.S. Sen. Mark Pryor, D-Ark., said Wednesday.

"We have put language in the defense authorization bill that says they can’t do this, this year," Pryor told reporters.

An Air Force proposal in February to cut its budget by $487 billion over the next decade received an icy reception in Congress because the cuts fell heavily on the Air National Guard.

Congress approved a temporary budget resolution that extends until March that included a restriction on the Department of Defense from making any such changes – including shifting the 188th Fighter Wing mission at Fort Smith to drones.

The Air Force has since come up with an unofficial revised plan aimed at softening congressional opposition so the service can begin shifting missions now. The plan would retain more A-10s within the Air Guard, allowing for bases in Michigan and Indiana to keep the mission.

Pryor met with Sen. Carl Levin, D-Mich., who chairs the Senate Armed Services Committee, to discuss his concerns and was reassured that the freeze would remain in place.

Like Pryor, Levin has struggled to get any documentation from the Air Force to justify the proposed cuts to the Air Guard.

"For 10 months now we have been stonewalled," Pryor said. "They’re not answering (Levin’s) questions, either. So, what we’ve been able to do is put language in the defense authorization bill that says they can’t do it this year."

The bill also calls for the Air Force to establish a more open process for evaluating mission changes that it intends to propose to Congress, Pryor said.

The Senate began debate on the bill Wednesday but may not complete action on it until next week, Pryor said.

The defense authorization would run through the fiscal year that closes at the end of September 2013. The battle would likely pick up again when the Pentagon unveils its 2014 budget early next year.

"The underlying issue still is with the 188th. The Air Force just does not understand the value. They are not tracking on why it is so important," Pryor said.

Beyond the benefit to the Fort Smith economy, Pryor said that the A-10 mission is a national security asset – providing joint training for Navy Seals, Green Berets and others using Fort Chaffee in Fort Smith.

"They will tell you they love having the A-10s there," Pryor said.

The Arkansas delegation sent a letter earlier this week to Air Force Chief of Staff Gen. Mark Welsh inviting him to Fort Smith to see for himself the benefits of the 188th Fighter Wing.

Pryor said that letters were sent to Senate and House chairs of relevant committees urging them to keep the prohibition on the Air Force as a final version of the defense authorization bill is negotiated.