Dismissing overtures from some supporters, Sen. John Thune (R-S.D.) said Tuesday that he will not run for president in 2012, reaffirming a decision he reached this year to forego a White House bid to instead seek a senior leadership post in the Senate.

Thune, a telegenic 50-year-old conservative with one Senate term under his belt, was considered by some GOP activists as the so-called fresh-face candidate who could present a proper generational challenge to President Obama. His initial rejection, in late February, came before a series of other potential top-tier candidates also took a pass on the 2012 race, creating what some Republican establishment figures in Washington see as a vacuum in the race.

Thune, however, dismissed that idea in an interview Tuesday. “My view on that hasn’t changed. I’m focused on the Senate,” he said. “I'm gonna keep focused on my work here.”

This reaffirmation of his intentions came after Bill Kristol, editor of the conservative Weekly Standard magazine, declared on C-SPAN Monday that Thune was again thinking about jumping into the race .

Thune acknowledged Tuesday that some unnamed supporters had talked to him about changing his mind, but that he waved off the entreaties. He complimented the candidates that are in the race, while adding that the field is “probably not as wide as people thought” it would be.

Thune's no-go means this will be the first presidential campaign in the modern era of televised politics without a sitting senator running for the White House.

Regardless, Thune's medium-range future lies squarely in the Senate, and putting to rest any presidential ambition is necessary to help him secure support for a higher-profile position in the Senate. He currently serves as the No. 4 GOP leader, chairman of the Republican Policy Committee, but with Sen. Jon Kyl (R-Ariz.) retiring, the No. 2 slot of GOP whip is up for grabs in a leadership election slated for just after the 2012 elections.

Thune has considered going for the whip job, but two others have publicly declared their intentions for that post: Sen. Lamar Alexander (R-Tenn.), chairman of the Republican Conference, considered No. 3 in leadership; and Sen. John Cornyn (R-Tex.), chairman of the National Republican Senatorial Committee.

Instead, Thune may run for the No. 3 slot that Alexander is vacating, which, if successful, would place him in charge of the communications effort for Senate Republicans. Sen. Mike Johanns (R-Neb.), a former governor, has announced his intention to run for that slot.

On Tuesday, Thune declined to state which job he would campaign for, noting that the campaign for those leadership posts would not begin for some time.