Senate Minority Leader Mitch McConnell on Tuesday said that by holding votes on nominees Democrats were trying to avoid amendment debate on a defense bill and divert attention from the issue of Iran sanctions.

The Kentuckian is not the first Republican to decry the potential lack of debate on the annual defense authorization legislation — earlier Tuesday, Sen. Tom Coburn of Oklahoma threatened to delay the bill unless more amendment votes were held — but the leader was the most direct in ascribing ulterior motives to the maneuvering.

“What I think ought to be done on the defense bill, instead of doing all these nonessential nominations this week, we ought to be turning to the defense bill and opening it up for … amendments as we’ve always done in the past,” McConnell said. “This is a rather transparent attempt to prevent a vote on enhanced Iran sanctions.”

He called the agreement between House and Senate defense leaders in conjunction with the lack of amendment debate an effort to “circumvent the Senate.”

Of course, both Democrats and Republicans worked on the deal that would clear the defense bill before Christmas. And before Thanksgiving, objections from GOP senators to votes on agreed-upon amendments helped bring a debate on the defense bill to a halt. But tensions between the two parties in the aftermath of a move from Majority Leader Harry Reid to change the Senate rules are threatening to complicate an already uneasy situation.

Also before Thanksgiving, the Nevada Democrat tried to assure members seeking tougher Iran sanctions that he would give them time on the floor. But that assurance now seems more politically expedient and as a result of frustration with the stalled defense bill than a commitment to the cause.

With the emerging objections of both Senate rank and file and Republican leadership, the chances for clearing a bill that has been signed into law every year for 51 straight years are as murky as ever.