President Trump is meeting next week with Republican senators in a push to get a congressional tax reform bill on his desk by Christmas, with a final vote purportedly coming as early as Thursday.

Trump will join the Senate Republican Policy Committee on Tuesday for the group’s weekly luncheon, upon Congress returning from a week-long Thanksgiving break.

This is the second time in the past few weeks that the president has gone to Capitol Hill to persuade fellow Republicans in the GOP-controlled Senate to back the tax reform bill, with yes votes from several holdouts still needed to pass the measure with a simple, 51-vote majority.

Trump and GOP Senate leaders can afford to lose only one or two votes, considering they have just a 52-48 majority over Senate Democrats, who do not support the legislation.

“We look forward to welcoming President Trump to the Senate again,” Wyoming Republican Sen. John Barrasso, chairman of the policy committee, said Friday. “This is a historic opportunity for our conference and the president to build on our momentum to give Americans the tax relief they’ve been waiting for.”

Republican Sens. Susan Collins, Maine; Lisa Murkowski, Alaska; and Ron Johnson, Wisconsin, are among those who have yet to back the bill.

"We've got a very small window, about a dozen days," former Trump campaign manager Corey Lewandowski on Saturday told Fox News' "Fox & Friends," while suggesting those who vote “no” jeopardize Republicans' control of Congress after next year's midterm elections.

The House, which is controlled by Republicans with a much larger majority than they have in the Senate, passed its version of tax reform several weeks ago with no Democratic support.

Trump is eager to pass major tax reform -- the first in nearly three decades -- to get his first major legislative victory.

"We're going to give the American people a huge tax cut for Christmas,” Trump said last week. “Hopefully, that will be a great, big, beautiful Christmas present."

This past summer, the House passed an ObamaCare replacement plan. But the Senate ultimately failed after several attempts, maddening Trump to the point of publically chastising Senate Majority Leader Mitch McConnell, R-Ky.

If the Senate passes the tax legislation, GOP lawmakers from the separate chambers would negotiate a compromise bill for Trump to sign into law. The separate versions each cut individual and corporate tax rates but with different strategies.

Last week, the Tax Policy Center, a joint operation of the liberal-leaning Urban Institute and Brookings Institution, concluded that low-earners would generally get smaller tax breaks than higher-income people under the Senate plan.

The top Democrat on the Senate Finance panel, Oregon Sen. Ron Wyden, said the study showed that "middle-class Americans will ultimately see a tax hike under Republicans' plan while corporate sponsors line their own pockets with multi-trillion-dollar giveaways."

A McConnell spokeswoman cited a study by the conservative-leaning Tax Foundation that concluded the bill would produce higher wages, nearly 1 million new jobs and enough economic growth to generate nearly $1.3 trillion in federal revenue.

The Senate bill would also repeal an ObamaCare requirement that Americans have health insurance or pay a fine, which is a project to save the federal government billions.

Fox News’ Chad Pergram and The Associated Press contributed to this report.