Updated

Senate Majority Leader Bill Frist (search), R-Tenn., is relying on his fund-raising strength to try to oust his Democratic rival — Senate Minority Leader Tom Daschle (search), D-S.D. Frist has helped funnel more than $150,000 so far this year to Republican John Thune (search), who is trying to unseat the three-term Daschle in what is expected to be one of the most competitive Senate races.

In 2002, Thune lost to Democratic Sen. Tim Johnson (search) by 524 votes in South Dakota, a Republican-leaning state that President Bush won handily two years earlier.

Like most House and Senate leaders, Frist has a political action committee that he uses to help Republican candidates. PACs can only donate $10,000 to a candidate, but Frist is accepting donations for Thune through his leadership PAC.

The practice is commonly used by advocacy groups, which typically tell financial backers to write checks to like-minded candidates, but it is less commonly used by politicians. Sheila Krumholz, research director for the nonprofit Center for Responsive Politics, said the practice represents a legal way for donors to win favor with congressional leaders.

"If you want to maximize your access to Frist, this is yet another way to do that," Krumholz said. "After you've maxed out to his campaign committee or his political action committee, you could also then give to candidates through his leadership PAC."

Linus Catignani, a consultant who helps run Frist's political action committee, said the Senate Majority leader started advising about 120 political supporters about GOP candidates they should consider supporting. Catignani says no one is pressured.

"Participation is based on whether they personally have an interest in the race and whether it is something they feel strongly about," Catignani said.

Frist and Daschle have a cordial relationship, but election-year politics could change that. The Republican plans to raise money for Thune on Daschle's home turf in South Dakota next month, according to Thune campaign manager Dick Wadhams.

Frist helped recruit Thune, a former House member, two years ago to run against Johnson and did so again this year against Daschle.

In all, Frist's PAC gave Republicans about $430,000 during the three-month period that ended March 31, according to a report filed with the FEC. That leaves the PAC with $1.6 million to spend before Election Day.