Senate Republicans were still working out the mechanics of the “debt triggger” for their tax bill Wednesday evening, even as the major tax bill advanced to the Senate floor.

“Anything you’ve heard, you can take off the table, because it’s evolving,” said Sen. Bob Corker, R-Tenn., the main proponent of the trigger.

Corker, a self-proclaimed deficit hawk, has bargained for including the trigger, which would automatically scale back the tax cuts if federal revenues subsequently came in lower than projected.

Republicans said at Tuesday night’s vote to proceed with the tax bill that the details were still being hammered out behind the scenes. They voted anyways to begin amending the bill and moving it toward final passage.

“We are going to saddle up and ride,” said Louisiana Sen. John Kennedy following the hastily-called vote. “We are going to put this bill on the floor ... and we’re going to start debating this bill and start talking about triggers and everything else in front of God and country and the American people. And we’ll stay here as long as it takes.”

All Republicans voted to advance the bill, even though some said they opposed the trigger concept.

“It's getting mixed reactions,” said Ohio Sen. Rob Portman.

Corker indicated that the trigger would only apply to the tax cuts that are currently included in the bill, around $1.5 trillion in total.

Others, though, suggested that the provision could also call for automatically phasing in spending cuts if the deficit rose by more than expected.

Texas Sen. Ted Cruz said that he was still aiming to have the trigger also provide for bigger tax cuts if revenues turned out to be higher than thought.