WASHINGTON (AP) — President-elect Joe Biden’s victory in November was tempered by concerns that he would face Republican opposition in the Senate that could stymie him at every turn.

Those worries eased this past week when Democrats swept two Senate special elections in Georgia, giving the party control of Congress and the White House for the first time since 2011. And the bipartisan outrage over the violent insurrection at the Capitol by pro-Donald Trump supporters could, at least for a moment, ease the partisan tensions that have paralyzed the legislative process for years.

Biden ran for office pledging to enact the boldest legislative agenda since the Great Depression, passing everything from a massive stimulus to combat the pandemic to trillions of new spending to address climate change, expand health coverage and tackle economic inequality. To accomplish even a slice of his plans, he will have to expertly navigate a Congress that, while in Democratic hands, is closely divided.

The Senate will be split evenly, with Vice President-elect Kamala Harris casting the tiebreaking vote when needed. The 222-211 Democratic majority in the House is the party’s narrowest in decades.

That means major legislation probably will not advance without at least some Republican support. GOP Sen. Mitch McConnell of Kentucky, the current majority leader, has shown skill in keeping his party united against Democratic priorities.

Passing major legislation is “still a challenge in a 50-50 Senate,” said Illinois Sen. Dick Durbin, the second-ranking Democrat.

“We can win simple majorities, but you have to face those 60-vote margins,” he said, referring to the number of votes needed to overcome a filibuster.

Biden will also have to cope with higher expectations after Georgia’s results than if he had faced a Republican-controlled Senate. That could lead to battles with progressive Democrats who want to push the new administration further left than it likes.