“It is critically important and I don’t think anybody knows it is stuck in a tax bill,” said Senator Maria Cantwell, the Washington Democrat who led the 2005 fight against drilling in the refuge. “It’s been around for thousands of years, and for no good reason we’re going to change it? Is there no such thing as a special place?’’

The current effort to allow drilling, the latest in a long series, stands the best chance of success in years thanks to a rare alignment of the political stars: Republicans control the House, Senate and White House. The tax bill is critical to the political future of the president and the Republican Party. And, the linchpin: A key role belongs to Senator Lisa Murkowski, Republican of Alaska, who has worked to allow drilling in the refuge her entire career.

The political landscape in Washington also has become more polarized since the last time Arctic drilling was a real possibility. When Senator Cantwell tried to strip the drilling provision out of the budget bill in October, it failed mostly along party line votes. Senator Susan Collins of Maine was the only Republican to support the effort.

The moment seems certain to be decisive on both sides of the battle.

Drilling proponents see the measure as one of responsible energy development for the good of Alaska and the nation. Oil and gas production in a portion of the refuge would generate $1.1 billion over the next decade, according to the nonpartisan Congressional Budget Office. And, proponents note, every barrel of oil from America is one not purchased from overseas.

For environmental activists, protecting the refuge is about preserving the fragile beauty of the Arctic wilderness — where caribou herds calve, polar bears den and millions of migratory birds gather — just as the effects of global warming are becoming more pronounced in the far north than almost anywhere else on earth.