The GOP tax reform bill narrowly passed in the Senate early Saturday morning, 51 to 49.

Senator Bob Corker was the only Republican to vote against the bill.

The passing of this plan has drawn criticism from Democrats, who were largely kept in the dark for the majority of the legislative process.

"It's gone through the regular order. The Democrats had plenty of notice. Chairman Hatch can attest to all of multiple hearings, markups, open amendment process. Everybody had plenty of opportunity to see the measure," said Senate Majority Leader Mitch McConnell. "You complain about process when you're losing."

The House and Senate now have to come together to combine both of their plans and then vote again on that final piece of legislation before sending it to the president's desk. 

The GOP and the White House are hoping to pass it before Christmas.