"This is a historic day, and we are happy warriors," U.S. House Democratic Caucus Chairman John Larson, D-Conn., said on CNN's "State of the Union" Sunday.
"We are so proud of the Democratic caucus, that we will be a part of history, joining Franklin Delano Roosevelt's passage of Social Security, Lyndon Johnson's passage of Medicare and now Barack Obama's passage of healthcare reform."
Larson acknowledged on ABC's "This Week" Democrats could lose seats for supporting the bill. "But it isn't about how many members are going to lose their seat," he said. "What the president said is right. It's about this moment. It's about the truth. It's every reason why you were elected to come and serve in Congress."
John Cornyn, R-Texas, chairman of the Republican Senate Campaign Committee, told "Fox News Sunday" the measure would face hundreds of amendments in the Senate.
"We're going to help the American people understand by these amendments what is in the bill and why they are right when they think it's a bad bill," he said. "The American people don't want this bill, but our Democrat friends seem determined to jam it down their throat regardless, and I think there are going to be some very serious consequences. But we're going to highlight that with our amendments."
Sen. Orrin Hatch, R-Utah, told CNN the measure would hurt Medicare by cutting its spending $500 million, increase taxes and fine people who can't afford insurance as well as businesses that don't provide employees health insurance.
"You reach a point where you say, who is going to pay for all of this?" Hatch said. "And it's going to come down to us taxpayers. And like I say, it's the Europeanization of America, and that's the worst thing that could possibly happen to our country."
House Minority Leader John Boehner, R-Ohio, said on NBC's "Meet the Press" Democrats and Republicans could agree on healthcare reform measures, as the parties had discussed at the White House.
"But what the American people don't want is this big government takeover of our healthcare system," he added, repeating a familiar GOP complaint that Democrats say has no basis in reality.
Democrats said the measure would extend health insurance to more than 30 million Americans who have none, cut healthcare costs, reduce the deficit and forbid insurance companies to deny coverage because of pre-existing conditions.
"We have a system where the health insurance industry continues to increase premiums by huge amounts, turn down constituents for coverage based on pre-existing conditions, find little fine print in healthcare policies to deny access to care when people need it the most, and that the status quo is just unacceptable," Rep. Chris Van Hollen, D-Md., said on "Face the Nation" on CBS. "And that has built this consensus to get this done."