But even with the GOP set to assume control of both ends of Pennsylvania Avenue, there were signs of discord within the party. House Republicans voted behind closed doors Monday night to retrench an independent ethics office – defying party leaders and complicating Trump’s “drain the swamp” campaign mantra.

Republicans will be under intense pressure to unify behind common goals in the era of Trump, after being plagued for years by infighting in Congress and on the campaign trail. They have identified a list of legislative priorities beginning with the repeal of the Affordable Care Act that they hope will energize most of the GOP. But the could face significant speed bumps.

Tuesday promises to be a day of both ceremonial rituals and consequential business on Capitol Hill. Members of the new House and Senate will be sworn in during the afternoon. Republicans will hold a 52-48 advantage over Democrats in the Senate; their edge in the House will be 241-194.

The House will elect its speaker on Tuesday afternoon, a position Paul D. Ryan, R-Wis., is expected to continue to hold. After a tumultuous campaign in which Ryan and Trump sometimes clashed, relations appears to have been smoothed over for the moment.

Part of the reason is Vice President-elect Mike Pence, a former member of Congress who enjoys a good relationship with both men. Pence plans meet with House Republicans on Wednesday to talk about the way forward on repealing the federal health-care law, according to an aide.

Federal budget legislation containing the repeal could be introduced in the Senate as early as Tuesday. But Democratic opposition to a repeal and complex Senate rules mean that core pieces of the 2010 health-care overhaul are likely to remain, including the legal framework for the individual mandate and pieces of the state exchanges the law created.

Further complicating matters: Republicans have yet to unite around replacement plan or on when such a plan should take effect.

Health care is one of many issues Republicans plan to address during the next two years. Pence said in a December speech that Trump has a “mandate” for leading and he identified a long list of priorities for the new administration and Congress. Among them: nominating a conservative Supreme Court justice and reworking the nation’s tax laws. Tackling such issues has proven to be a contentious process in the past.

Republicans must also focus in the coming weeks on getting Trump’s Cabinet nominees confirmed. Democrats plan to resist some of Trump’s picks.

In the House, members will vote on a rules package Tuesday amid intense scrutiny on the proposed changes to the Office of Congressional Ethics (OCE). The office was created in 2008 to address concerns that the Ethics Committee had been too timid in pursuing allegations of wrongdoing by House members.

The 119-to-74 vote during the Monday GOP conference meeting means that the House rules package expected to be adopted would rename the OCE as the Office of Congressional Complaint Review and place it under the oversight of the House Ethics Committee.

Under the proposed new rules, the office could not employ a spokesperson, investigate anonymous tips or refer criminal wrongdoing to prosecutors without the express consent of the Ethics Committee, which would gain the power to summarily end any OCE probe.

Ryan and Majority Leader Kevin McCarthy, R-Calif., opposed the amendment to the House rules package. But Judiciary Committee Chairman Bob Goodlatte, R-Va., pushed it. His office said it “provides protections against any disclosures to the public or other government entities.”

Democratic leadership said the changes appear to run counter to Trump’s vows to rid the nation’s capital of corruption and other underhanded dealings.

“Republicans claim they want to ‘drain the swamp,’ but the night before the new Congress gets sworn in, the House GOP has eliminated the only independent ethics oversight of their actions,” said Minority Leader Nancy Pelosi, D-Calif., in a statement. “Evidently, ethics are the first casualty of the new Republican Congress.”

In the Senate, Democratic leaders say they stand ready to work with Trump on areas where they can find common ground, such as infrastructure investments and trade. But they warn that they will not hesitate to fight him on areas where they disagree.

“It is not our job to be a rubber stamp. It is our job to do what’s best for the American people, the middle class and those struggling to get there,” Sen. Charles E. Schumer, D-N.Y., plans to say Tuesday in his first floor speech as the leader of the Senate Democrats, according to excerpts of his remarks provided by his office.

Schumer also plans to challenge Trump to rely on more than Twitter as he prepares to become the 45th president. The president-elect is known for firing off tweets at all hours of the day. Often, the messages are blunt attacks against his critics.

“‘Making America Great Again’ requires more than 140 characters per issue,” Schumer plans to say.

Tuesday will also mark a farewell of sorts for Vice President Joe Biden. Biden, who served in the Senate for decades before joining the Obama administration, will preside over the Senate as president of the chamber.

Biden has drawn attention in the past for colorful moments during the swearing-in ceremonies of senators and photo-ops with their families.

The Washington Post’s Kelsey Snell, Karoun Demirjian, Paul Kane and Ed O’Keefe contributed to this report.