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A closely divided Senate voted to approve oil drilling in an Alaska wildlife refuge, a major victory for President George W. Bush (search) and a stinging defeat for environmentalists who have fought the idea for decades.

By a 51-49 vote, the Senate (search) on Wednesday put a refuge drilling provision in next year's budget, depriving opponents of the chance to use a filibuster to try to block it. Filibusters, which require 60 votes to overcome, have been used to defeat drilling proposals in the past.

"This project will keep our economy growing by creating jobs and ensuring that businesses can expand," Bush said in a statement. "And it will make America less dependent on foreign sources of energy, eventually by up to a million barrels of oil a day."

Environmentalists for years have fought such development, contending it would lead to a spider web of drilling platforms, pipelines and roads that would adversely impact the calving grounds of caribou, polar bears and millions of migratory birds that use the refuge's coastal plain.

Republican Sen. Ted Stevens (search) of Alaska, who has fought for 24 years to open the Arctic National Wildlife Refuge to oil companies, acknowledged it still could be "a long process" before a final drilling measure clears Congress. Lawmakers must agree on the final budget.

Also, the House did not include an Arctic refuge measure in its budget, a difference that will have to be worked out in future negotiations.

Nevertheless, the Senate made clear by Wednesday's vote that a majority now supports tapping what is believed to be 10.4 billions or more of barrels of oil within the refuge's 1.5 million-acre (600,000-hectare) coastal plain. Two years ago, a similar attempt to use the budget process to open the refuge failed by three votes.

But that was before Republicans last November expanded their majority, adding several senators who favor drilling. Only seven Republicans, all moderates, bucked their party Wednesday and voted with most Democrats against opening the refuge.

Environmentalists said while the vote was disappointing, they haven't given up the fight. "It only strengthens our resolve to protect America's most pristine national wildlife refuge for our children's future," said Larry Schweiger, president of the National Wildlife Federation.

"The battle is far from over," said Lexi Keogh of the Alaska Wilderness League. She said environmentalists will push to keep the ANWR provision out of a final budget document.

The oil industry has sought for more than two decades to get access to the oil. In 1980, Congress said the oil could be developed, but only if lawmakers specifically authorized the Interior Department to sell oil leases. Repeatedly Congress has failed to do so.

Drilling opponents argued that more oil would be saved than ANWR could produce if Congress enacted an energy policy focusing on conservation, more efficient cars and trucks and increased reliance on renewable fuels.

Drilling supporters countered that the refuge's oil can be pumped while still protecting the environment and wildlife.

Modern technology, drilling techniques and environmental restrictions would dramatically limit the industrial footprint that would be left on the tundra and protect wildlife, said Murkowski. "We know we've got to do it right. ... It's a fragile environment."

One Republican senator after another argued that with foreign imports accounting for more than half of the oil America uses, every available barrel should be pursued. The Alaska refuge represents the largest potential onshore oil find in the country, they said.

But drilling opponents rejected the suggestion that ANWR's oil would have much impact on global markets, today's high oil and gasoline prices, or the continued U.S. reliance on foreign producers.