The decision that Sen. John Thune (S.D.) makes after the elections on whether to give up his Conference chairman job to run for Whip or National Republican Senatorial Committee chairman could trigger a scramble among ambitious GOP Senators.

Thune’s current job is the No. 3 leadership post in the party, but he has repeatedly said he is keeping his options open. Any move by Thune will likely put him in a contested race.

Because the NRSC post brings with it the opportunity to build a national donor network, the job might be attractive to Thune, who is considered a potential future presidential or vice presidential candidate. 

But Jerry Moran (Kan.) and Marco Rubio (Fla.) are also potential NRSC candidates, Senate GOP sources said. And Moran, at least, appears to be seriously considering it.

It’s unclear whether Thune wants to take on the role of NRSC chairman, which involves extensive travel and the often thankless task of raising campaign funds. “He’s not setting himself up,” a GOP adviser said. “You don’t see him out there rallying the troops … laying the foundation you need to do to get to the NRSC chair.”

 Thune’s Heartland Values PAC has given nearly $250,000 to candidates in the past two years and $30,000 to the NRSC.

Senate GOP sources said Moran is exploring a run for NRSC chairman. But he has been in the Senate less than two years and may not have the fundraising potential of a national figure like Thune or Rubio. One source said Moran’s interest in the race is an attempt “to show ambition,” which could help position him for a future bid for a leadership spot.

“Sen. Moran appreciates his colleagues encouraging him to run for NRSC chairman, but he is currently focused on making certain Republicans gain a majority in the Senate and win the White House this November,” a Moran spokesman said. “Through his work with FreeState PAC, Sen. Moran is traveling the country to raise money and has given to nearly every Senate candidate this cycle. Following Election Day in November, he will consider how he can be most helpful in the 2014 elections.”

Federal Election Commission records show that Moran’s PAC has given nearly $150,000 to Senate and House candidates and $15,000 to the NRSC during the 2012 cycle.

Rubio has also been mentioned as a possible NRSC chairman, but that may be more wishful thinking among his fans than an actual desire by the Floridian to take on the duties of chief fundraiser.

A Rubio spokesman did not rule out a run but stressed that the Senator is focused on helping GOP presidential nominee Mitt Romney and other candidates crucial to the Republican effort to win a Senate majority, including Rep. Connie Mack IV (Fla.), who is facing Sen. Bill Nelson (D-Fla.). So far this cycle, Rubio’s Reclaim America PAC has funneled nearly $70,000 to Senate candidates.

Still, the NRSC job could be good for Rubio if he has ambitions to climb the leadership ladder or seek the presidency, GOP sources said.

“It [will likely get current NRSC Chairman John] Cornyn to the Whip position,” one source said, who noted that Minority Leader Mitch McConnell (Ky.)and former Majority Leader Bill Frist (Tenn.) served as NRSC chairmen. “It’s not a glamorous job. But what it does do is build a lot of good will and immediate alliances and stronger friendships. … It’s a great spot to build a base of support.”

Thune would face an uphill climb for the Whip post. Cornyn is the only declared candidate for the second-ranking leadership post. Current Whip Jon Kyl (Ariz.) is retiring.

Cornyn has been seeking commitments from his colleagues since last year, which gives him a leg up on any challengers, GOP sources said. Plus, Cornyn could benefit from any gains the party makes in the Senate in November, particularly if he helps make McConnell Majority Leader.

Despite being the frontrunner, sources said Cornyn does not expect an uncontested ride into the Whip position. “Cornyn seems to anticipate some challenge, but from whom is an unknown,” one GOP operative said. 

But with the GOP leadership elections coming within three weeks of the presidential election, there will be little time for anyone to mount a challenge, the operative noted.

If Thune decides to run for a new post, possible candidates for Conference chairman include John Barrasso (Wyo.), who is now Republican Policy Committee chairman – a position considered the proving ground for future Conference chairs. But Roy Blunt (Mo.),  who became Republican Conference vice chairman in January, could also throw his hat into the ring.

Sens. Mike Johanns (Neb.) and Ron Johnson (Wis.), who have both sought leadership positions in the past, could also be candidates for Conference vice chairman and policy committee chairman.