The budget blueprint for fiscal 2007, which will begin in October, includes a $10 billion Gulf Coast restoration fund that would be financed from the leasing of arctic refuge drilling rights, revenue from new drilling in the Outer Continental Shelf of the Gulf of Mexico and further sales of the broadcast spectrum. With that provision in hand, Landrieu cast the only Democratic vote for the budget resolution, which squeaked through Thursday night, 51 to 49.

"It's not easy being alone on anything. I don't relish this position," Landrieu said. "But, at times, it's necessary."

Republicans, who have been trying to open up the refuge for well over a decade, hope that by explicitly linking oil drilling to Gulf Coast restoration, they can prompt some Democrats to drop their opposition. Under the Senate plan, the funds from oil leases could be used for coastal restoration projects in Texas, Louisiana, Mississippi and Alabama that have long been sought by environmentalists. The fund could also be tapped to rebuild levees damaged last year by hurricanes Katrina and Rita.