The U.S. Senate on Tuesday voted to advance William Barr's nomination to be U.S. attorney general, teeing up a swift confirmation vote that is expected to take place later this week.

Senators voted, 55-44, to curtail debate on Barr's nomination, with the vote falling largely along party lines. Three Democrats—Sens. Joe Manchin of West Virginia, Kyrsten Sinema of Arizona, and Doug Jones of Alabama—voted to advance Barr's nomination to a final floor vote. One Republican—Sen. Rand Paul of Kentucky—opposed Barr, while Sen. Cory Booker, D-New Jersey, did not vote.

A final confirmation on Barr's nomination could come as early as Wednesday or Thursday. If Barr—currently of counsel at Kirkland & Ellis—is confirmed, it'll be his second time leading the Justice Department. He was previously U.S. attorney general during the George H.W. Bush administration. Before that, Barr had also served as a deputy attorney general and headed the Justice Department's Office of Legal Counsel.

Barr is all but guaranteed to be confirmed, thanks to the Senate's GOP majority.

But the nominee has still faced intense Democratic opposition, thanks in part to a legal memo Barr sent to Justice Department officials and members of Trump's personal legal team in June 2018 about Special Counsel Robert Mueller III's probe into Russian interference in the 2016 U.S. election. In the memo, Barr described a possible obstruction of justice inquiry into the president as “fatally misconceived.” Sen. Dianne Feinstein, D-California, the top Democrat on the Senate Judiciary Committee, has described Barr's letter as “disqualifying.”

Democrats have also expressed dissatisfaction over Barr's refusal to commit to the full release of Mueller's findings to the public, once the special counsel's work has concluded.

Barr, during his confirmation hearing, vowed to “provide as much transparency” as possible in sharing Mueller's findings with lawmakers and the public. But the nominee's response also left open the possibility that he would only release his summary of Mueller's findings to the public, rather than releasing the special counsel's own prepared report.

“I am going to make as much information available as I can consistent with the rules and regulations that are part of the special counsel regulations,” Barr said during his hearing.

Some of Barr's defenders have said the nominee wouldn't have been able to meet Democrats' demands for a commitment to releasing Mueller's findings.

Jonathan Turley, a professor at George Washington University's law school, told senators last month that Barr could not “commit in advance” to releasing information he had not yet reviewed because “part of his duty is to protect” grand jury-related or privileged information.

“He's duty-bound to review that,” Turley told Senate Judiciary Chairman Lindsey Graham, R-South Carolina.