WASHINGTON -- The Capitol rang with vows to fix the crisis-ridden economy Tuesday as Congress opened for business.

"We need action and we need action now," said Speaker Nancy Pelosi.

Republicans agreed, and pledged cooperation in Congress as well as with president-elect Barack Obama -- to a point.

On a day largely devoted to ceremony, members of Congress swore to defend the Constitution. The Senate galleries were crowded; children and grandchildren of lawmakers squirmed in their seats in the House chamber as the winners in last fall's elections claimed their prizes.

One office-seeker was not among them.

Charles Dharapak ~ Associated PressIllinois U.S. Senate appointee Roland Burris leaves Capitol Hill on Tuesday after he was turned away when he appeared to take his seat.

In a scripted bit of political theater, Democrat Roland Burris of Illinois was informed he would not be seated because his paperwork was not in order. He pledged a lawsuit, a continuation in a situation that began when he was named to Obama's Senate seat by Gov. Rod Blagojevich, who has been charged with having attempted to sell the appointment.

Obama was across town in a meeting with his economic advisers as the opening gavels fell in the House and Senate at noon. His inauguration as the nation's first black president is two weeks away.

Senate Majority Leader Harry Reid, a veteran of numerous battles with President Bush, made plain how glad he was the old administration was winding down.

"We are ready to answer the call of the American people by putting the past eight years behind us and delivering the change that our country desperately needs," he said on the Senate floor. "We are grateful to begin anew with a far more robust Democratic majority."

At the same time, in comments directed at Republicans, he said, "we are in this together" when it comes to the economy, the wars in Iraq and Afghanistan, health care and the country's energy needs.

Sen. Mitch McConnell of Kentucky, the Republican leader, replied in a speech of his own, saying, "The opportunities for cooperation are numerous." He said Democrats should avoid a "reckless rush to meet an arbitrary deadline" to pass an economic stimulus bill that could reach $1 trillion, and he outlined possible changes in the approach Obama and the Democratic congressional leaders have been considering.

Among them was a proposal to cut taxes by 10 percent. Another was to lend money to hard-pressed state governments rather than give it to them. "States will be far less likely to spend it frivolously" in that case, he said.

McConnell will soon be the most powerful Republican in government after elections that handed Democrats the White House and left them with gains of least seven seats in the Senate and 21 in the House.

McConnell's counterpart in the House, Republican leader John Boehner of Ohio, handed the speaker's gavel to Pelosi in a traditional unity tableau. He, too, pledged cooperation, then said, "America's potential is unlimited. But government's potential is not. We must not confuse the two."

House Democrats pushed through a series of rule changes, including one that calls for greater disclosure of earmarks.

They also repealed the six-year term limit for committee chairman. It was a legacy of the Republican Revolution that swept through Congress in 1994. In all, 34 senators were sworn in, and apart from the controversy involving Burris, one other Senate seat was in limbo.

Democrat Al Franken holds a 225-vote lead over former senator Norm Coleman in Minnesota, a result certified Monday by the state Canvassing Board. He has not yet received a certificate of election, and with Republicans threatening to protest, Democrats made no attempt to seat him.