House Republican leadership scored a rout over Democrats and detractors in their own conference Wednesday by passing a short-term debt limit bill as Democratic opposition crumbled and Republicans provided a relatively unified vote on a major spending bill.

In effect, Republicans won by scaling back their expectations, deciding at their annual retreat in Williamsburg, Va., last week to abandon the insistence on dollar-for-dollar spending cuts for a debt limit increase and replace it with a demand that the Senate pass a budget.

But Wednesday’s feel-good debt ceiling increase does not forebode tranquility. Many conservatives joined Speaker John A. Boehner of Ohio in part because of promises he made to hold firm in future battles, and the speaker will be hard pressed to keep the coalition intact through the pitfalls ahead.

The bill would suspend the debt limit through May 18, then automatically increase the current $16.4 trillion ceiling to accommodate additional debt accumulated before that date.

The legislation also would tie congressional pay to passage of a budget plan by suspending salaries of members of the House or Senate if either chamber does not adopt a resolution by April 15. Lawmakers would be paid at the end of the 113th Congress should their pay be delayed.

Although he had promised not to negotiate over the debt limit, the scheme won tacit approval from President Barack Obama, who signaled he would sign the bill. Senate Majority Leader Harry Reid, D-Nev., said he will pass it through the Senate unchanged.

House passage puts heat on Senate Democrats to place their spending priorities into legislative text. Perhaps more important, it sets the field of play on which Congress will have to deal with automatic spending cuts, or the sequester, and the coming expiration of a continuing resolution to fund the government.

Those battles should be bruising, in part because in order to wrangle votes from his own conference, Boehner promised five influential conservatives he would push a budget that would balance in 10 years and keep spending levels at or below those set under the sequester’s cuts.

Boehner told reporters Wednesday that he has not yet spoken with Obama or Reid about how to deal with the sequester but established in no uncertain terms that the cuts are real.

“The sequester is going to go into effect on March 1 unless there are cuts and reforms that get us on a plan to balance the budget over the next 10 years. It’s as simple as that,” he said.

Rep. Steve Southerland II of Florida, the sophomore class’s delegate to the GOP leadership table, said that because half of the cuts come from defense, the chambers will look for a way to replace them with reductions elsewhere in the budget. But he added that absent an agreement, Republicans are willing to allow the blunt force approach to kick in.

“The only thing worse than the cuts that are in sequestration are no cuts at all. We are teetering dangerously into a financial abyss,” he said.

That kind of insistence on budget cuts already is causing problems for defense hawks in the Republican Conference. And even the relative GOP unity on the plan didn’t provide enough votes to carry it without Democratic support.

“Republicans produced 199 votes. They just don’t seem to be able to get to 218,” House Minority Leader Nancy Pelosi told reporters.

Rep. C.W. Bill Young of Florida, chairman of the Defense Appropriations Subcommittee, said he will spend the coming months trying to convince members that the cuts to defense would be devastating.

“My goal right now is to tell them that along with sequestration, extending the CR for the balance of the year is threatening to defense,” he said. “The government is bloated and there are plenty of ways to make savings, but it should be done carefully, especially with defense.”

He voted for the debt limit bill, however, as did other hawks, including Rep. Duncan Hunter, R-Calif., a veteran and member of the House Armed Services Committee. He said he did so, “on the belief that we have enough members that don’t want to cut the military.”

Still, for the moment, House Republicans are rejoicing that their gambit worked. It did so as House Democratic leaders strongly criticized the legislation but didn’t take any serious steps to stop it.

While Obama and Reid gave the bill consent, House Minority Whip Steny H. Hoyer of Maryland ripped it on Tuesday, as “worthy of almost unrestrained derision.”

But his office was sending mixed signals. While he urged Democrats to vote against the bill in a whip email, Democrats in marginal districts were getting a different message: Vote however you need to, according to a Democratic leadership aide.

The contrast between Democrats’ words and actions on the issue shows the political peril they face from a GOP strategy to highlight the Senate’s inability to pass a budget for almost four years. Even top Democrats admit they’re in a tough spot.

“I give you an ‘A’ for political tactics and an ‘F’ on economic policy,” House Budget ranking member Chris Van Hollen of Maryland recounted telling Majority Whip Kevin McCarthy of California and House Budget Chairman Paul D. Ryan of Wisconsin at Monday’s presidential inauguration ceremonies.

Even though the GOP demand to raise the debt ceiling is relatively modest, Democrats are now playing the GOP’s debt limit game — they’re engaged on negotiating over it, which is exactly what Republicans had planned and is the opposite of what the president had repeatedly vowed.

Emily Holden contributed to this report.