The Republican-led House of Representatives passed energy legislation last year that would have opened ANWR to drilling, but a Democratic-led Senate did not pass similar legislation.

The White House contends that the refuge's potential 16 billion barrels of crude must be tapped to help reduce U.S. dependence on oil imports from unfriendly countries like Iraq.

But many Democrats and environmentalists oppose drilling, saying the administration should cut oil imports by boosting the mileage standards of gas-guzzling sport utility vehicles.

Six of the Senate's 51 Republicans, including former presidential candidate John McCain of Arizona, last week announced they would not go along with a plan to tack ANWR drilling language onto a massive spending bill this spring that would enact the new 2004 budget for the federal government.

"Because the opening of the Arctic refuge to drilling raises a host of policy concerns, including serious environmental ramifications, we do not believe this issue should be injected in the budget process," the lawmakers said in a letter to Senate Majority Leader Bill Frist and Senate Budget Committee Chairman Don Nickles.

The letter is the latest twist in a two-year legislative battle over drilling in the Alaskan refuge.

The Democratic-led Senate last year soundly defeated efforts to open the refuge, when drilling supporters fell short of the 60 votes needed to end debate on the controversial proposal and allow a final vote on the measure.

DRILLING BACKERS DON'T WANT A FILIBUSTER

To get around a filibuster this time around, supporters of opening the refuge want to attach drilling language to must-pass legislation to fund the 2004 budget for the federal government. They argue that such language is appropriate for budget legislation because of the fees the government would collect from leasing tracts in the refuge to oil companies.

Under Senate rules, budget legislation cannot be filibustered and only 50 votes would be needed to approve the bill and an attached ANWR drilling provision.

In addition to McCain, the letter was signed by Senators Olympia Snowe and Susan Collins of Maine, Lincoln Chafee of Rhode Island, Peter Fitzgerald of Illinois, and Mike DeWine of Ohio. The six were part of a group of eight Republicans who crossed the aisle last year to vote against ANWR drilling.

In his State of the Union speech to Congress earlier this week, President George W. Bush urged lawmakers to pass legislation enacting his national energy plan, which includes drilling in the refuge.

Two Democratic presidential hopefuls, Senators John Kerry of Massachusetts and Joseph Lieberman of Connecticut, oppose ANWR drilling and have promised to filibuster any energy bill that would open the refuge.

A new poll released last week by The Wilderness Society showed that by a two-to-one margin, voters reject opening the Arctic refuge to oil drilling, even in the case of impending war with Iraq and a possible cut-off of some of America's oil supplies from the Middle East.

Meanwhile, the Senate Energy Committee announced last week a series of hearings that will focus on the energy challenges facing the United States and will also guide the development of comprehensive energy legislation.

"My top priorities will be hammering out a robust and diverse energy bill for floor consideration this summer," said panel chairman Pete Domenici.

"Right now, America is faced with energy challenges and opportunities. We are on the brink of war in the Middle East and dangerously dependent on Middle East oil," he added.

The panel will hold three hearings in February on oil and natural supplies, and energy production on federal lands - which could include drilling in the Arctic refuge.