Updated at 4:36 p.m. ET

Democrats took exceedingly narrow control of the Senate on Wednesday after winning both runoff elections in Georgia, granting them control of Congress and the White House for the first time since 2011.

Democrat Jon Ossoff defeated Republican David Perdue, according to The Associated Press, making him the youngest member of the U.S. Senate and the first Jewish senator from Georgia. Earlier Raphael Warnock, a pastor from Atlanta, defeated GOP Sen. Kelly Loeffler after a bitter campaign. Warnock becomes the first Black Democrat elected to the Senate from a Southern state.

The Senate will now be split 50-50 between the two parties, giving Vice President-elect Kamala Harris the tiebreaking vote.

Loading...

Ossoff had a narrow lead Wednesday morning when he declared victory.

"It is with humility that I thank the people of Georgia for electing me to serve you in the United States Senate," he said.

Perdue has not conceded.

Impact on Biden agenda

Control of the Senate significantly changes what President-elect Joe Biden could do, but most importantly, his party will now be able to set the legislative agenda. Democrats failed to make the kind of gains in Senate races in November that many had forecast, with GOP incumbents staving off strong challenges in several states. But with narrow control, they will wield the gavels for Senate committees, call hearings and decide which items get top priority.

Sen. Chuck Schumer of New York is expected to replace GOP Sen. Mitch McConnell as majority leader and will determine which bills come to the floor for votes.

The ambitious proposals addressing climate change and health care and other domestic priorities touted by Biden and Harris will be difficult, if impossible, to advance with more moderate Democrats — especially those facing competitive 2022 midterm reelection campaigns — reluctant to sign onto partisan proposals. The much smaller-than-anticipated House Democratic majority compounds the challenge for the party.

Instead, Biden will need to consider which domestic priorities can get bipartisan support since Senate rules now require anything to get 60 votes to advance. The president-elect has already indicated that additional coronavirus relief will be his first priority, but he has also said he plans to unveil an infrastructure plan that could get support from Republicans.

In a statement Wednesday, Biden said that "Georgia's voters delivered a resounding message yesterday: they want action on the crises we face and they want it right now. On COVID-19, on economic relief, on climate, on racial justice, on voting rights and so much more. They want us to move, but move together."

The president-elect also spoke to Democrats' potential total control of Washington.

"It looks like we will emerge from yesterday's election with Democratic leadership in the House and the Senate, and of course I'm pleased that we will be able to work with Speaker [Nancy] Pelosi and a Majority Leader Schumer," Biden said. "But I'm also just as determined today as I was yesterday to try to work with people in both parties — at the federal, state and local levels — to get big things done for our nation."

Democratic control will ease passage for Biden's Cabinet nominees. It's unclear with the short time between setting up committees and negotiating staff arrangements in the narrowly split chamber what that will mean for how quickly confirmation hearings and floor votes could happen with just two weeks before the inauguration.

Return of the bipartisan gangs

After months of stalemate over the size and scope of a coronavirus relief package in the closing weeks of the last Congress, a group of centrists from both parties, led by Democratic Sen. Joe Manchin of West Virginia and Republican Sen. Susan Collins of Maine, unveiled a $900 billion compromise plan that became the basis for the legislation that ultimately was approved by the House and Senate and signed by President Trump.

Manchin has said he hopes that model can translate into efforts in 2021.

Other Republican moderates such as Sen. Mitt Romney of Utah and Sen. Lisa Murkowski of Alaska who helped on the COVID-19 aid package could also serve as powerful players if they decide to work across the aisle.

Progressives push for Senate rule changes

Liberal Democrats have pressed to get rid of the legislative filibuster so that they can pass major health care or environmental bills with a simple majority.

Biden has sidestepped questions about whether he supports doing away with keeping the 60-vote threshold, but several top Senate Democrats have signaled they back changing a rule that many of them once insisted was essential to the institution. There will be intense pressure on Biden and Democratic leaders to show they can pass some bills with GOP support, but if Senate Republicans stay largely unified to thwart the new administration's agenda, calls to eliminate the filibuster will increase.

Manchin has publicly said he will oppose any effort to change the rules, and he will have outsize influence in the closely divided chamber.

Copyright 2021 NPR. To see more, visit https://www.npr.org.