Sen. John Thune (R-S.D.) sat tense, crouched and glowering as the base-closing commission delivered its verdict about Ellsworth Air Force Base in the ballroom of a Crystal City hotel yesterday, then leapt up gleefully when the bomber base's death sentence was commuted.

The 44-year-old's political career may have been spared as well.

Last fall, Thune unseated Senate Minority Leader Thomas A. Daschle (D-S.D.) in part by claiming that a Republican tight with the White House would have a better chance of saving the perennially impaired Ellsworth, a Cold War arsenal in the middle of the prairie. So it was potentially calamitous for Thune back home in May when the Pentagon put Ellsworth on the list of closure recommendations for the independent Base Realignment and Closure commission.

Thune, a former House member whose status as the Daschle slayer has made him a popular speaker before GOP groups, had long told the White House that losing Ellsworth -- South Dakota's largest employer after the state government -- was the one issue that could make him a one-term senator.

"There's something about my Scandinavian heritage that knows that life shouldn't be easy -- life's got to be hard," a relieved Thune said by telephone shortly after the commission's 8 to 1 vote to discard the Pentagon recommendation to close Ellsworth and move the base's B-1B bombers to Texas.

Thune, who has traveled the country raising money for Republicans, said he has done almost nothing but focus on Ellsworth since the May announcement. He personally lobbied Vice President Cheney, White House Chief of Staff Andrew H. Card Jr. and Defense Secretary Donald H. Rumsfeld. He dined one-on-one with BRAC commissioners and showed up at hearings where he was not able to speak, just so he could stare them down.

"It's been a 24-7 proposition," Thune said.

The senator even took the risky move of expressing his displeasure with the administration by announcing his opposition to President Bush's controversial nomination of John R. Bolton as ambassador to the United Nations.

Thune said "a couple of things that we did late in the game were pretty persuasive," including calling attention to a lawsuit that could tie up airspace around Dyess Air Force Base in Texas, where the bombers were to go. Thune also argued in a marathon series of interviews over the summer that putting the whole bomber fleet at one base was not smart because more of them could be destroyed by a tornado or a terrorist strike. And commissioners publicly questioned the Pentagon's savings estimates.

Larry J. Sabato, founder and director of the University of Virginia's Center for Politics, said Thune "was on the fast track to a national ticket or Senate leadership until Ellsworth was threatened."

"Now he can claim another great triumph, and he's established some independence from the White House," Sabato said. "Given Bush's unpopularity, Republicans may be looking for a non-Bush figure who still keeps the conservative faith."

Steve Hildebrand, Daschle's campaign manager, said Thune, who won by two percentage points after losing a Senate race two years before, is likely to have a strong challenger when he seeks reelection in 2010. "He's still going to have to watch his back every step of the way," Hildebrand said.

Sen. John Thune (R-S.D.), right, is congratulated by New Mexico Gov. Bill Richardson (D) after the commission spared Ellsworth Air Force Base.