Yet GOP senators made compromises everywhere—except with Democrats. In the end, self-described deficit hawks voted for legislation that, according to the nonpartisan Joint Committee on Taxation, would increase the nation’s budget gap by $1 trillion over a decade even after factoring in economic growth. Supply-siders allowed tax cuts for individuals to expire after six years while making them permanent for corporations. And Republicans who blanched at gutting Obamacare earlier this year agreed to eliminate the law’s individual mandate as part of the tax bill.

Passage of the proposal sets up negotiations with the House on a final bill for President Trump to sign that would represent the most far-reaching change to U.S. tax policy in more than 30 years, as well as the most significant one-party legislation to pass since the Affordable Care Act in 2010. Republicans hope to enact their tax package by Christmas.

Aside from Corker’s defection, Saturday’s vote was a rare display of unity from a Senate Republican conference that could not agree on a repeal of Obamacare earlier this year. And it showed how much more comfortable Republicans are with cutting taxes than with just about any other legislative issue, much less health care. Supporters of the bill said it would deliver tax relief, on average, to families at every income level while putting U.S. businesses on a more competitive footing with their global competitors.

Democrats countered it would do nothing of the sort.

“With the passage of this tax bill, today will be the first day of a new Republican party – one that raises taxes on the middle class, abandoning its principles for its political paymasters,” Senator Charles Schumer of New York, the Democratic leader, said in the lead-up to the vote.

In the end, Republicans decided to essentially ignore a late report from the congressional Joint Committee on Taxation finding that their bill would add $1 trillion to the debt over 10 years because it wouldn’t translate to the kind of economic growth party leaders had promised. The nonpartisan analysis came out on Thursday at the same time that GOP deficit hawks, led by Corker and Jeff Flake of Arizona, were learning that their proposal for a provision triggering future tax increases would not comply with Senate budget rules.

But rather than accommodate the deficit hawks by scaling back the tax cuts, party leaders won the final critical votes elsewhere. They deepened tax breaks for so-called “pass-through” businesses to win over Senators Ron Johnson of Wisconsin and Steve Daines of Montana. Bowing to Senator Susan Collins of Maine, they restored a state-and-local property-tax deduction up to $10,000. And they made Flake a completely unrelated commitment to work on a fix for undocumented immigrants who are at risk of deportation starting in March, when Trump ends former President Barack Obama’s Deferred Action for Childhood Arrivals program.