Alabama Sen. Richard Shelby has put a hold on the confirmation of President Barack Obama’s pick for a key Department of Defense position amid the continued controversy over an Air Force tanker contract.

Obama’s nomination for Pentagon acquisitions is Ashton Carter. But Shelby has blocked the confirmation, reports the Associated Press.

Shelby, of course, represents the state where Northrop Grumman and EADS would build their KC-30 tanker. The other contender for the $35 billion deal, The Boeing Co., would build its KC-767 in Washington.

Washington Sen. Maria Cantwell also moved to block a similar nomination last year if the Pentagon failed to start the tanker contest over.

There has been much speculation over whether the two companies should split the contract, as discussed in this piece.