Two childhood friends are bankrolling Paige Kreegel’s bid to win a U.S. House seat.

They set up a $1 million super-political action committee that spread Kreegel’s message on Florida television, by automated telephone calls and in the mail when his own campaign couldn’t afford to do so. Their contributions to the super-PAC, Values Are Vital, amounted to about 10 times the sum Kreegel raised from other donors for the race.

Today, they will find out if there’s a return on their investment in a Republican primary that will likely determine the next representative, given the district’s partisan bent. Kreegel, who lost a run for the same seat in a crowded primary in 2012, benefited this year from the super-PAC’s intimidating role, he said in a videotaped interview last month with the Naples Daily News editorial board.

“It did keep us from becoming a six-way race,” said Kreegel, who is facing two serious competitors in tonight’s vote. “It’s done its job.”

Such candidate-specific super-PACs in congressional and Senate races are the latest development in the changing campaign-finance landscape. A Bloomberg review of U.S. Federal Election Commission filings has identified at least 40 such entities, with more forming each week.

Eight of the 12 most competitive Senate races are buzzing with individual super-PAC activity as Republicans work to pick up the six seats they need to take control of the chamber in November. Democrats are also starting outside groups. Wolfheel PAC, a group that will assist Democratic Senator Kay Hagan’s re- election in North Carolina, registered with the FEC in January.

Corruption Threat

The risks of such dependence on wealthy backers, who may later have legislative interests before Congress, alarms campaign-finance and government watchdog groups.

“It is a ridiculous charade to think that super-PACs don’t lead to corruption,” said Paul S. Ryan, senior counsel for the Campaign Legal Center, a nonprofit based in Washington that favors restricting outside groups.

In addition to friends, families are getting into the action. Nebraska Senate candidate Ben Sasse’s great uncle gave $100,000 in March to get a super-PAC going to help his relative win a contested Republican primary. Representative George Holding, a North Carolina Republican, won his 2012 election after a super-PAC called American Foundations Committee helped with ads. Its donor list reads like a family reunion: cousins, uncle, aunt.