House Democratic leader Nancy Pelosi of California was somewhat more partisan in her acceptance speech to the House. Her calls for more diversity and immigration restructuring drew standing ovations from Democrats, while most Republicans stayed in their seats, not applauding.
"The strength of our democracy will be advanced by bold action for comprehensive immigration reform," she said.
In the Senate, Republicans took the less conciliatory tone. Minority Leader Mitch McConnell, R-Ky., who helped craft the fiscal cliff deal, called it "imperfect," though he said it had settled Washington's long debate about raising revenue.
"The president got his revenue; now it's time to turn squarely to the real problem, which is spending," he said. "In a couple of months, the president will ask us to raise the nation's debt limit. We cannot agree to increase that borrowing limit without agreeing to reforms that lower the avalanche of spending that's creating this debt in the first place. It's not fair to the American people."
The Democratic leader urged calm. "The recent effort to avert the fiscal cliff was an example of both the divisions and the collaborations that will mark a moment in history - and it was a moment in history," said Senate Majority Leader Harry Reid of Nevada.
The new Congress began with slightly more Democrats than its predecessor had. The party now controls 55 Senate seats, up two from the last Congress. In the House, Republicans have a 233 to 200 majority, down eight seats.
The makeup is slightly different. For the first time, the House Democratic caucus doesn't have a majority of white men. Eighteen percent of House members and 20 percent of senators are women. Nineteen percent of House members and 6 percent of senators are minorities.
Senators who won election or re-election were called in alphabetical small groups and sworn into office by Biden, who's the president of the Senate. Sen. Tim Scott of South Carolina made history as the first African-American senator from the South since Reconstruction and the first African-American Republican senator since Ed Brooke of Massachusetts left in 1979.
Sen. Tammy Baldwin, a Wisconsin Democrat who defeated popular former Republican Gov. Tommy Thompson for the Senate seat vacated by Democrat Herb Kohl, became the first openly gay senator.