Democrats have taken control of the US Senate after Vice-President Kamala Harris swore in three members to give the party a narrow grip on both houses of Congress as well as the White House for the first time in a decade.
The first of President Joe Biden's cabinet nominees won Senate approval on Wednesday night: Avril Haines, tapped for the job of director of national intelligence.
Democrats Raphael Warnock and Jon Ossoff of Georgia and Alex Padilla of California took the oath of office in the Senate chamber hours after Biden and Harris were sworn in.
Warnock and Ossoff won upset victories in a pair of January 5 runoff elections to split the Senate 50-50 with Harris, a Democrat, holding the decisive vote in any tie between Republicans and Democrats.
Padilla, California's first Latino senator, was appointed to fill Harris's Senate seat after she resigned on Monday to assume the second highest US office.
Swearing in the new senators, Harris laughed after she read out her own name as the California senator who had resigned, declaring: "Yeah, that was very weird, OK."
The three Democrats give Biden a narrow advantage to pursue policies that include a fresh wave of relief for a nation hammered by the coronavirus pandemic in the face of deep political divisions.
The new arrangement makes Democratic Senator Chuck Schumer the majority leader, with Republican Mitch McConnell demoted to minority leader.
Schumer and McConnell pledged to work together and McConnell pledged to work also with Biden, a former senator McConnell has known for years.
Schumer and McConnell are in talks about a possible power-sharing deal governing daily Senate operations. Both men favour making such an agreement but McConnell has asked to keep the rules requiring a supermajority of 60 votes to advance most legislation.
The shifting Senate control has complicated already-delayed efforts to get Biden's cabinet nominees confirmed. In past years, at least some national security nominees have been confirmed on inauguration day.
Schumer said the Senate would address the health and economic crises of the pandemic and strive to make progress on racial justice, adding: "Make no mistake, the Senate will forcefully, consistently and urgently address the greatest threat to this country and to our planet - climate change."
The new Senate is poised to hold former President Donald Trump's second impeachment trial on a charge of inciting insurrection passed by the House last week after his supporters stormed the Capitol. It was unclear when the trial would begin.
Democrats also hold a 221-211 majority in the House of Representatives.
Warnock, a 51-year-old Baptist preacher, is the first black senator to represent Georgia. He held the pulpit in Atlanta where slain civil rights leader Martin Luther King Jr once preached.
Ossoff, 33, is the youngest senator sworn in to the Senate since Biden, who took office in 1973 at age 30.
Padilla, 47, was California's secretary of state.
Australian Associated Press