ON MY FINAL DAY ABOARD the Healy, as I don a flight suit and wait for the helicopter to take me ashore before the ship heads north for its next mission, the government is still wrestling with what to do about the Arctic. In Washington, a top-level policy review is almost complete. Since the Healy is one of only three U.S.-owned polar icebreakers, Congress is considering funding two new vessels. (Russia has 18.) And no matter what the Healy discovers next week, making claims will be a complicated process. The U.S. is the only Arctic country that has not yet acceded to the Law of the Sea Treaty, despite the odd alliance of environmentalists (who like its ecological protections) and the Bush administration (which likes its provisions for territorial claims). That means no American scientists sit on the treaty board to analyze claims. And it means the claims made by other Arctic nations may be granted before the U.S. even joins. "If this were a ballgame," says Rear Admiral Brooks, "the United States wouldn't even be on the field."

Underlying the worries over the treaty and the rapid melting is a question I asked everyone I met in Washington and Alaska who was connected with the Bush administration: Does the White House finally believe global warming is real? Chertoff told me he was "agnostic" about what caused the warming. "The reality is there's less ice. The larger question is what to do about it." Then he and Commandant Allen listed concerns about the consequences. How will the Coast Guard monitor the expected flood of vessels? How will the U.S. and Russia cooperate to prevent oil spills or collisions as ships back up, waiting to get through the Bering Strait? Who will represent U.S. interests up north? The U.S. does not have a permanent Arctic base yet. At the moment, Allen said, the Healy is the eyes and ears of the U.S. in the Arctic.

A few hours after the helicopter ride, I leave on the 8 P.M. Alaska Airlines flight out of Barrow. The Healy, out at sea, has turned toward the pole. Gray clouds obscure land, but after a while I see the green peaks of the Brooks Range below, the winding rivers around Fairbanks, swelled by melted ice, and rows of floatplanes at the airport. I turn to my row companion, a Frenchman wearing an earring. Xavier Mouy works for a Canadian firm, Jasco Research.

"I was on the Beaufort Sea, doing a marine-mammal survey," he says good-naturedly.

"For whom?" I ask, and once again the answer conjures the warming Arctic, the rush for a new world.

"Shell Oil."