WASHINGTON – The Senate on Tuesday narrowly defeated a proposal that would have delayed the next round of domestic base closings until the Pentagon determines what it wants to do with its overseas facilities.

The 49-47 vote was a victory for the Pentagon, which opposes any delay in next year’s round of base closings. The proposal, by Sens. Trent Lott, R-Miss., and Byron Dorgan, D-N.D., was made as an amendment to a bill authorizing $422.2 billion in defense programs next year.

But the House this week will consider a two-year delay in base closings as part of its version of the defense bill. Last year, the White House threatened a veto if the plans were delayed.

Base closings have long been a politically charged issue in Congress, where lawmakers fear the economic damage that could occur in their states and districts.

Republican Sens. Olympia J. Snowe and Susan M. Collins of Maine both voted for the delay.

“Particularly as we continue operations in Afghanistan and Iraq, it makes no sense to consider closing nearly a quarter of our domestic military infrastructure in addition to the 21 percent already lost over the past 15 years here in America,” said Snowe, adding that she would continue “to fight this ill-advised base closing process.”

Dorgan said the Pentagon won’t know what domestic bases it will need until it decides what it will do overseas.

“You’re going to bring 50,000 Army troops from Germany back to American soil – where are you going to put them?” he asked. “Wouldn’t you want to make those decisions before you have a base closing decision here for domestic bases?”

Defense Department officials see the base closings as a necessary cost-cutting measure at a time of tight budgets. Leaders of the Senate Armed Services Committee agreed with them that the closings are needed as part of an overall restructuring of the military.