WASHINGTON — Senate Democrats Monday threatened a filibuster to stop Republicans from adding language to a must-pass defense spending bill that would allow oil drilling in Alaska's Arctic National Wildlife Refuge (ANWR).

The refuge, an area the size of South Carolina that sprawls along Alaska's northern coast, has been at the center of a bitter congressional debate for decades. The refuge is home to caribou, polar bears, migratory birds and other wildlife.

Tapping ANWR's estimated 1 million barrel per day crude oil output is a top priority of the Bush administration to increase oil supplies and slow imports. Senate Democrats and moderate Republicans say tougher fuel standards for sport utility vehicles and minivans could save the same amount of oil.

Senate debate on the measure began on Monday morning, a few hours after the U.S. House of Representatives approved a $453.3 billion defense budget bill in a pre-dawn vote with the controversial ANWR drilling provision attached to it.

Furious Democrats said including ANWR in funding for U.S. soldiers and Pentagon weapons programs violated Senate rules that require a spending bill to include only germane items.

"These tactics reflect poorly on this body and this leadership," said Sen. Russ Feingold, a Wisconsin Democrat, "Funding for our brave men and women in uniform should not be jeopardized by opening ANWR to drilling."

Democrats first planned a parliamentary procedure to challenge the ANWR language in the bill, saying it was added by negotiators and did not appear in the original versions of the House and Senate defense spending bills.

If Republicans override the chamber's parliamentary ruling with a simple majority of 51 votes, Democrats said they would launch a filibuster to talk the bill to death.

"I don't have any hesitation to be a part of a filibuster," said Democrat Joseph Lieberman of Connecticut. "This is a fight worth waging."

Republicans must have 60 votes to end a filibuster, cutting off debate and allowing a bill to have a vote.

"This is a Christmas package designed for delivery to the oil industry, and we have got to fight as hard as we can to stop that delivery," said Sen. Frank Lautenberg of New Jersey.

The fiery debate over ANWR drilling could keep the Senate in session until Wednesday, according to aides.

Republican Sen. Ted Stevens of Alaska pushed to get the drilling plan included in the annual defense budget because it was the only major bill moving through the Congress that ANWR could hitch a ride on.

"Oil is related to national security. This is an amendment to pursue domestic production of oil," Stevens said. "The largest consumer of oil in the United States is the Department of Defense."

His state would get half the estimated $10 billion that energy companies would pay for ANWR drilling rights if oil prices were at $50 a barrel, according to government estimates. The federal government would receive the other half.

"This is nothing more than a sweetheart deal for Alaska and the oil companies," said Sen. Maria Cantwell, a Democrat from Washington state.

About 1.5 million acres of the refuge's coastal plain would be opened to drilling under the current congressional plan.

If Congress opened ANWR to drilling, the refuge's oil would not flow into market for 10 years, according to the U.S. Energy Information Administration.

Once the refuge reached peak production in 2025, its oil would shave about 2 percentage points off the share oil imports would have in meeting domestic demand, the EIA said. That would moderate U.S. oil imports to a forecast 58 percent of total demand in 2025, equal to current import levels.

Source: Reuters