First, Trump and his fellow Republicans would have to find a way to work together.

‘Drain the swamp’

He repeatedly promised to “drain the swamp” of the Washington establishment and has called House Speaker Paul Ryan “a weak and ineffective leader.” Ryan and Senate Majority Leader Mitch McConnell almost always avoided speaking Trump’s name in public, and while they nominally supported him, they never campaigned alongside him.

Republicans who will control the Senate are sharply divided over matters that include immigration, trade and climate change.

Indeed, some Republicans weren’t even willing to vote for Trump, and few have embraced some of his signature proposals, such as building a wall on the border with Mexico and enacting 35 percent tariffs on Mexican imports from U.S. companies. Republican Senator Lindsey Graham of South Carolina said on Twitter that he voted for an independent candidate for president. Republicans Jeff Flake of Arizona and Ben Sasse of Nebraska also spoke out strongly against Trump.

"We now have a country to run," Graham said in a statement posted on Twitter. "President-elect Trump and the new Congress will face many challenges. We have wars to win, threats to be dealt with and a stagnant economy which must be revived. To the extent that I can help President-elect Trump, I will do so."

Maine Senator Angus King, an independent who caucuses with the Democrats, in a statement Wednesday called on all sides to "look to one another with compassion and understanding, to view each other as neighbors rather than adversaries." He added, "It will be difficult, but it is achievable."

The party also faces significant challenges in the Senate because it still lacks the 60 votes needed to force through most legislation over Democratic objections. Republicans could change the rules to keep Democrats from blocking Trump’s Supreme Court nominees, including one to replace the late Justice Antonin Scalia.

One big winner on the night was McConnell, whose gamble to block Merrick Garland’s nomination to the high court paid off. The Trump win put an end to Democrats’ dreams of a liberal court; progressive interest groups were relishing the prospect that the court would have a majority of Democratic appointees for the first time since 1969.

The three oldest Supreme Court justices all support Roe v. Wade, the landmark abortion rights ruling that Trump has predicted would be overturned by his court picks.

October surprises

Republican Senate candidates were victorious amid an uncertain electoral landscape that was complicated by high disapproval ratings for both Trump and Democratic nominee Hillary Clinton. Surprise developments in the campaign’s closing weeks weakened both White House aspirants, including a tape of Trump bragging about groping women and FBI Director James Comey’s shock announcement 11 days before the election that his agency was looking at more Clinton e-mails.

The list of Republican incumbents who survived tough Democratic challenges was long, and started with Marco Rubio of Florida, whose decision to run for the Senate after an all-hands-on-deck recruitment effort by GOP leaders dramatically boosted their prospects for keeping hold of the chamber.

John McCain of Arizona, Richard Burr of North Carolina, Roy Blunt of Missouri, Pat Toomey of Pennsylvania and Ron Johnson of Wisconsin also won re-election, and Representative Todd Young defeated the Democrats’ star recruit in Indiana, former Senator Evan Bayh.

In an otherwise disastrous evening for Democrats, the party gained a seat in Illinois, as Representative Tammy Duckworth ousted incumbent Mark Kirk. They also managed to salvage Harry Reid’s Senate seat in Nevada, with Catherine Cortez Masto defeating Representative Joe Heck, making her the first Latina to ever win a Senate seat.

Republicans took over the Senate two years ago after losing control to Democrats in 2006. The GOP could add to its majority in 2018, when 25 of the 33 seats up for election are held by Democrats and two independents who caucus with them.

GOP House

On the House side, Republicans easily cleared the 218 seats needed to control the chamber, losing only a handful of races.

Republican incumbents in Florida were ousted, including former House Transportation and Infrastructure Chairman John Mica and David Jolly, who was defeated by party-switching former Governor Charlie Crist. The Democrat who defeated Mica in Florida, Stephanie Murphy, came to the U.S. as a Vietnamese refugee.

Also falling in the Republican ranks was Representative Scott Garrett of New Jersey, a senior member of the Financial Services Committee who chairs the subcommittee on capital markets and government-sponsored enterprises.

Ryan will likely win credit from many Republicans for helping them to run campaigns that kept some strategic distance from Trump, even as many probably benefited from Trump-fueled turnout. Even so, Ryan -- the party’s 2012 vice presidential nominee who became speaker a year ago after conservatives pushed Speaker John Boehner out of office -- could still see his own leadership under question for his less-than-full-throated support of Trump.

The speaker did energetically campaign and raise money for his House colleagues, even as some Republicans publicly complained of the potential harm they saw for GOP candidates from Ryan’s tepid backing of the presidential nominee. In the final days of the campaign, he started backing Trump more explicitly.

But it’s unclear how well Trump and Ryan will get along, or whether they can agree on an agenda, given their high-profile splits on immigration and trade.

Ryan congratulated Trump early Wednesday on his "incredible" win.

"It marks a repudiation of the status quo of failed liberal progressive policies. We are eager to work hand-in-hand with the new administration to advance an agenda to improve the lives of the American people," Ryan said in a statement. "This has been a great night for our party, and now we must turn our focus to bringing the country together."

Possibility of reconciliation

Even though Senate Republicans will have a slim governing margin next year, their control of the chamber and the House could let them make big changes to the tax code and health-care policy. That’s because of a powerful procedure called budget reconciliation that can allow the Senate to pass bills containing revenue- or entitlement-related changes with just 51 votes.

Republicans used the method to pass President George W. Bush’s tax cuts in 2001 and 2003, and it helped Senate Democrats push through the Affordable Care Act in 2010. Trump and virtually all Republicans in Congress agree that they want to repeal Obamacare as soon as possible. This year, they put a partial repeal on President Barack Obama’s desk.

He vetoed it.

This time, they’ll have a president who says he will sign it.

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