WASHINGTON — Democrats have decided to allow a quarter-century ban on drilling for oil off the Atlantic and Pacific coasts to expire next week, conceding defeat in an months-long battle with the White House and Republicans set off by $4 a gallon gasoline prices this summer.

The Appropriations Committee Chairman, Rep. David Obey, a Democrat of Wisconsin, told reporters today that a provision continuing the moratorium will be dropped this year from a stopgap spending bill to keep the government running after Congress recesses for the election.

Republicans have made lifting the ban a key campaign issue after gasoline prices spiked this summer and public opinion turned in favor of more drilling. President Bush lifted an executive ban on offshore drilling in July.

“If true, this capitulation by Democrats following months of Republican pressure is a big victory for Americans struggling with record gasoline prices,” the House GOP leader, Rep. John Boehner of Ohio, said.

Democrats had clung to the hope of only a partial repeal of the drilling moratorium, but the White House had promised a veto, Mr. Obey said.

Just last week, the House passed legislation to open waters off the Atlantic and Pacific coasts to oil and gas drilling but only 50 or more miles out to sea and only if a state agrees to energy development off its shore.

Republicans called that effort a sham that would have left almost 90 percent of offshore reserves effectively off-limits.

The Interior Department estimates there are 18 billion barrels of recoverable oil beneath coastal waters now off-limits.

While the ban on energy development will be lifted if the Senate goes along with the House action, it doesn’t mean any federal sale of oil and gas leases in the offshore waters — much less actual drilling — would be imminent.

The Interior Department’s current five-year leasing plan includes potential leases off the Virginia coast but probably would not be pursued unless the state agrees to energy development. And the state is unlikely to do so without Congress agreeing to share federal royalties with the state.

The congressional battle over offshore drilling is far from over. Democrats are expected to press for broader energy legislation, probably next year, that would put limits on any drilling off most of the Atlantic and Pacific coasts. Republicans, meanwhile, are likely to fight any resumption of the drilling bans that have been in place since 1981.

“The future resolution of offshore drilling will have to be addressed with a new president,” a spokesman for Speaker Pelosi, Drew Hamill, said in a statement.

Lifting the drilling ban gives considerable momentum to the underlying bill, which includes the Pentagon budget, $24 billion in aid for flood and hurricane victims and $25 billion in loans for Detroit automakers in addition to keeping the government open past the October 1 start of the 2009 budget year.

But Democrats decided not to use the must-pass measure as a battering ram to carry an extension of unemployment benefits for the long-term jobless past White House veto promises, prompting grumbling among some lawmakers. Efforts to boost food stamps and give states billions of dollars to help with Medicaid bills also fell through.

But the measure would double, to $5.2 billion, funding for heating subsidies for the poor, Mr. Obey said.

Mr. Obey said he hoped the stopgap bill would pass the House tomorrow.