“We will not allow this to stand,” Representative Michele Bachman, Republican of Minnesota, promised Monday afternoon as the House reconvened.

Democrats said they would focus on explaining the measure to their constituents and on highlighting some immediate benefits, and called on Republicans to ease off the attacks now that the legislation had passed.

“It is time to chill out, Republicans,” Representative Bob Filner, Democrat of California, said. “Let this bill work. Let our constituents finally get health care.”

But there were no signs of a ceasefire. Senate Democrats said they would take up a budget reconciliation measure containing the final revisions to the health care overhaul shortly after Mr. Obama signs the main bill at the White House ceremony on Tuesday.

Far from sounding a conciliatory note, Senate Republicans said they would employ every procedural maneuver available to try to derail the reconciliation bill, or at least punch holes in it by knocking out key provisions.

The Senate Republican leader, Mitch McConnell of Kentucky, quickly adopted a new rhetorical strategy on Monday, asserting that the revisions Democrats want to push through would make the health care law worse, not better.

“Democrat leaders now want us to take the bill that passed the Senate in December and that the House voted on last night and make the tax hikes even higher, the Medicare cuts even deeper,” Mr. McConnell said in a floor speech. “They want us to endorse a raft of new sweetheart deals that were struck behind closed doors last week so this thing could limp over the finish line last night.”

It was unclear whether that argument would gain traction, given that many of the changes in the reconciliation measure are aimed at adjusting provisions that the Republicans themselves had previously criticized, such as the so-called Cornhusker kickback that would provide extra Medicaid money for Nebraska.

Still, Mr. McConnell’s remarks answered a question Democrats had already begun asking about how Republicans would pivot in their opposition, now that the bulk of the health care overhaul legislation was about to become law.

Around the country, the reaction to the House passage of the bill was emotional, and in some cases violent.

Representative Gabrielle Giffords, Democrat of Arizona, said that her Tucson office was vandalized following her vote in support of the measure. A glass door was shattered, she said.

Following a weekend when protesters outside the Capitol subjected some Democratic lawmakers to racial slurs and epithets, Representative Randy Neugebauer, a conservative Republican from Texas, said on Monday that he was the lawmaker who shouted “baby killer” on the House floor Sunday night. The shout was heard while Representative Bart Stupak, a Michigan Democrat, was discussing abortion-related provisions in the health care bill, and it was widely taken to have been directed at him.

In a statement, Mr. Neugebauer, a third-term member of the House from Lubbock, said he got caught up in the passions of the moment and was not referring to Mr. Stupak personally but to the health care measure itself.

“In the heat and emotion of the debate, I exclaimed the phrase ‘it’s a baby killer’ in reference to the agreement reached by the Democratic leadership,” Mr. Neugebauer said. “While I remain heartbroken over the passage of this bill and the tragic consequences it will have for the unborn, I deeply regret that my actions were mistakenly interpreted as a direct reference to Congressman Stupak himself.”

Across the nation, Republican candidates seized on the passage of the health care legislation to bolster their effort to capture seats in Congress now held by Democrats.

“Last night, Washington thumbed its nose at the American people, taking over one-sixth of our nation’s economy and adding to the mountain of debt already looming over our children’s future,” said former Representative Rob Simmons of Connecticut, a Republican who hopes to replace Senator Christopher J. Dodd, a Democrat who is retiring.

“This is not the time to give up and go home,” Mr. Simmons said. “Now is the time to fight.”

Carl Hulse and Jeff Zeleny contributed reporting.

Idiots.