WASHINGTON Hours before Senate Republicans were scheduled to vote on a tax proposal that doesnt technically exist in final legislative form, Senate Majority Leader Mitch McConnell (R-Ky.) strode to the floor on Friday and said he was confident the bill would pass.

We have the votes, he told reporters.

McConnell was foiled over the summer and fall by the GOP effort to repeal and replace the Affordable Care Act, suffering a number of embarrassing defeats that illustrated his inability to wrangle the Republican Senate conference. Tax reform would be different, promised McConnell and other GOP leaders.

After months of negotiations and false starts, Republicans finally seem prepared to pass their most sweeping rewrite of the U.S. tax code in three decades.

To pass the bill, Republicans were forced to make significant last-minute changes, including some to a deduction for certain types of businesses. Republicans hadnt provided any detailed explanations or legislative text for the changes.

Sen. Jeff Flake (R-Ariz.), one of the last holdouts on the GOP bill, announced Friday morning that he would vote for the bill despite concerns that the legislation would add as the Joint Committee on Taxation said Thursday more than $1 trillion to the debt over the next 10 years.

From the outset of the current debate on tax reform, my goal has been to ensure that Congress passes a tax reform package that is both fiscally-responsible and promotes economic growth, Flake said in a statement.

Flake said hed obtained a firm commitment from Republican leaders and the Trump administration to protect beneficiaries of the Deferred Action for Childhood Arrivals program, and changes to a budgeting gimmick that made the bill seem less expensive than it actually is.

An agreement on DACA would be a significant development in the tax debate, as well as in a coming struggle over a year-end government funding bill. But Marc Short, the White House director of legislative affairs, told reporters Friday there was not yet an agreement on DACA, only a deal to include Flake in the discussions.