At the moment, on the Senate floor, a Republican-Democratic coalition is blowing up at a rump of conservative senators for trying to pose extra conditions on the budget process. What Ted Cruz and Rand Paul and Mike Lee want -- and have wanted -- is a guarantee that a debt limit increase cannot be included in the budget agreement that comes out of the House and Senate conference. It only takes 51 votes to pass a budget. Cruz, on the floor, has asked the Senate to preserve the "traditional 60-vote threshold" for raising the debt limit.
This is a strange definition of "tradition." Nobody likes to have a pro-debt limit vote on the record, so votes to raise it are usually pretty limited and partisan. In 2012, the last time the Senate gave the thumbs-up to a debt limit hike, it got only 52 votes. So the Cruz/Paul/Lee gambit will fail, it's in the interest of most Republicans that it fail, and the rebels get to say they, the proud and lonely few, stood and fought for the right for supermajority debt limit votes.