Republicans were demanding that they scrap the bill passed by the Senate last year without a single Republican vote, and House Democrats indicated they would not quickly approve the Senate’s version without changes and send it to President Obama.

Republican Party Chairman Michael Steele said the voters in Massachusetts had mirrorred the anxious mood of the nation by electing Mr. Brown, who campaigned against the Democratic measure and won the seat vacated by the death of Senator Edward M. Kennedy, its champion in the Senate.

”People across the country are saying, ’Slow it down,” Mr. Steele said Wednesday on ABC’s ”Good Morning America.” After a meeting of House Democratic leaders Tuesday night even as Mr. Brown’s victory was being declared, top lawmakers said they were weighing their options. But the prospect of passing the health care overhaul by pushing the Senate plan through the House appeared to significantly diminish.

Mr. Brown said on Wednesday that voters are “tired of the backroom deals” and would punish the Democrats if they tried to wiggle out of their predicament.

“If they use political chicanery, and they do it without having it go back and forth with proper votes, I think come the midterm elections people will be very concerned and they will remember,” he said on NBC’s “Today” show.

Noting that the election in Massachusetts turned on a variety of different factors such as the economy and local issues, Representative Chris Van Hollen, Democrat of Maryland and a top party campaign strategist, acknowledged that resistance to the emerging health legislation also factored in the outcome of the Massachusetts race.

“Health care was also part of the debate and the people of Massachusetts were right to be upset about provisions in the Senate bill,” Mr. Van Hollen said, referring to “special deals” included in the bill to win the votes of Democratic senators and round up 60 votes.

The comment was a clear indication that Democrats were recalibrating their approach on health care, leaving them a diminishing and politically difficult set of choices.

Pushing the Senate plan through the House was favored by some lawmakers and strategists as a way to quickly deliver the president a bill on a signature domestic achievement, since it would require just one final House vote. Remaining problems could be worked out with a subsequent piece of legislation.

But many House Democrats expressed deep reservations about the Senate bill. Those complaints, combined with the message sent by the Massachusetts electorate, apparently were sufficient to leave Speaker Nancy Pelosi and her lieutenants reluctant by Tuesday night about moving in that direction.

Democrats now face decisions on whether to give up on the health care fight – an approach few lawmakers appear willing to entertain – or perhaps pull together a scaled-back measure and use special procedural rules that would eliminate the need for 60 votes in the Senate. But it is not clear how many of the key provisions of the legislation could be passed under such a procedure.

In recent days, the White House and Congressional Democrats have been working to reconcile the differences between the Senate measure and a version of the legislation narrowly adopted by the House in November.

But getting a revised bill through both chambers and sent to President Obama’s desk would require Senate Democrats to once again produce the 60 votes needed to surmount a certain Republican filibuster, something now in doubt given that once Mr. Brown is sworn in, Democrats will control only 59 votes.

Sentiment about how to proceed was mixed, with several House lawmakers expressing wariness about accepting a Senate-passed plan due to their deep reservations about it. But top officials said that approach may be the party’s best alternative and most House members said they still believed it was crucial that Democrats pass a plan.

“It is important for us to pass legislation,” said Representative Baron Hill, a conservative Democrat from Indiana. Mr. Brown appeared likely to claim his seat quickly, as Democrats said their new Republican colleague would be sworn in as soon as he could present documents certifying his election. When he takes office, Democrats will no longer have the 60 votes needed to surmount a certain Republican filibuster of the legislation.

“The people of Massachusetts have spoken,” Senator Harry Reid, the Nevada Democrat and majority leader, said.

The timing of Mr. Brown’s swearing in has in fact been a point of contention. Republicans and conservative activists have raised the possibility that Democrats might stall and use the delay to force through a final health care bill while Senator Paul Kirk, the Democrat appointed to the seat, was still a member of the Senate.

Democrats had discounted that possibility and such a scenario seemed all but dead Tuesday as Senator James Webb, a Virginia Democrat and supporter of the measure, called for the Senate to take no votes on health care legislation until Mr. Brown joins them.

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