Senate Majority Leader Harry Reid told reporters Tuesday that the final product would be completed in 24 to 48 hours. It is being designed to achieve the support of at least two-thirds of the Senate's members -- the usual threshold for rules changes in the Senate.
Sens. Tom Udall (D-NM), Jeff Merkley (D-OR) and several allies had hoped to invoke the "Constitutional Option" -- a process that would have allowed them to change the rules (to whatever degree) at the beginning of this session of Congress. Udall in particular wanted to re-establish the precedent for its own sake -- to put the Senate on notice that there are consequences to abusing the rules.
But when support for that option diminished, and opposition intensified, the reformers gave way to their leaders. Though it's unlikely that any rules changes would have occurred without Udall's efforts, any changes to the rules will be invoked through the standard process.
The key moment occurred about two hours after Alexander's statement, when, on the Senate floor, Udall and Merkley were unable to obtain unanimous consent from the Senate to debate their rules reforms. The two could have appealed to the Senate's presiding officer, and pressed ahead. Precedent suggests they had the right to force the debate. But faced with daunting odds, they brought the constitutional option to a close.