COUNCIL BLUFFS, Iowa -- The biggest donors in the Republican Party are financing a new group to recruit seasoned candidates and protect Senate incumbents from challenges by far-right conservatives and Tea Party enthusiasts who Republican leaders worry could complicate the party's efforts to win control of the Senate.
The group, the Conservative Victory Project, is intended to counter other organizations that have helped defeat establishment Republican candidates over the last two election cycles. It is the most robust attempt yet by Republicans to impose a new sense of discipline on the party, particularly in primary races.
"There is a broad concern about having blown a significant number of races because the wrong candidates were selected," said Steven J. Law, the president of American Crossroads, the "super PAC" creating the new project. "We don't view ourselves as being in the incumbent protection business, but we want to pick the most conservative candidate who can win."
The effort would put a new twist on the Republican-vs.-Republican warfare that has consumed the party's primary races in recent years. In effect, the establishment is taking steps to fight back against Tea Party groups and other conservative organizations that have wielded significant influence in backing candidates who ultimately lost seats to Democrats in the general election.
The first test of the group's effort to influence primary races could come here in Iowa, where some Republicans are already worrying about who will run for the seat being vacated by Senator Tom Harkin, a Democrat. It is the first open Senate seat in Iowa since 1974, and Republicans are fearful of squandering a rare opportunity.
The Conservative Victory Project, which is backed by Karl Rove and his allies who built American Crossroads into the largest Republican super PAC of the 2012 election cycle, will start by intensely vetting prospective contenders for Congressional races to try to weed out candidates who are seen as too flawed to win general elections.
The project is being waged with last year's Senate contests in mind, particularly the one in Missouri, where Representative Todd Akin's comment that "legitimate rape" rarely causes pregnancy rippled through races across the country. In Indiana, the Republican candidate, Richard E. Mourdock, lost a race after he said that when a woman became pregnant during a rape it was "something God intended."
As Republicans rebuild from losing the White House race and seats in the House and Senate last year, party leaders and strategists are placing a heightened focus on taking control of the Senate next year. Republicans must pick up six seats to win a majority.
Representative Steve King, a six-term Iowa Republican, could be among the earliest targets of the Conservative Victory Project. He said he had not decided whether he would run for the Senate, but the leaders of the project in Washington are not waiting to try to steer him away from the race.
The group's plans, which were outlined for the first time last week in an interview with Mr. Law, call for hard-edge campaign tactics, including television advertising, against candidates whom party leaders see as unelectable and a drag on the efforts to win the Senate. Mr. Law cited Iowa as an example and said Republicans could no longer be squeamish about intervening in primary fights.
"We're concerned about Steve King's Todd Akin problem," Mr. Law said. "This is an example of candidate discipline and how it would play in a general election. All of the things he's said are going to be hung around his neck."
Mr. King has compiled a record of incendiary statements during his time in Congress, including comparing illegal immigrants to dogs and likening Capitol Hill maintenance workers to "Stasi troops" after they were ordered to install environmentally friendly light bulbs. But he rejected the suggestion that his voting record or previous remarks would keep him from winning if he decided to run for the Senate.
"This is a decision for Iowans to make and should not be guided by some political staffers in Washington," Mr. King said in an interview, pointing out that he won his Congressional race last year even though President Obama easily defeated Mitt Romney in Iowa. "The last election, they said I couldn't win that, either, and the entire machine was against me."
The Conservative Victory Project will be a super PAC operating independently of the National Republican Senatorial Committee. It will disclose the names of donors and raise money separately from American Crossroads, officials said, because some donors were uncomfortable about aggressively weighing in on Republican-vs.-Republican fights.
"It is a delicate and sensitive undertaking," Mr. Law said. "Our approach will be to institutionalize the Buckley rule: Support the most conservative candidate who can win."
But by imposing the rule of the conservative leader William F. Buckley, the group could run afoul of Ronald Reagan's "11th Commandment" to not speak ill of a fellow Republican.
In Iowa, Cory Adams, the chairman of the Story County Republican Party, said the criticism aimed at Mr. King was unfair and misdirected. He warned of resistance from conservative activists if outside groups tried to interfere in the Senate race.
"If he wants to run for the Senate, he should be allowed to run," Mr. Adams said of Mr. King, whose Congressional district includes Story County. "The more people get to know him, the more they will like him."
The retirement announcements last month from Mr. Harkin and Senator Saxby Chambliss, Republican of Georgia, have created wide-open Senate races that are expected to attract several prospective candidates. The Conservative Victory Project is working to build a consensus with other groups on candidates who have the strongest chance of winning.
Grover Norquist, who leads Americans for Tax Reform, a fiscally conservative advocacy group that plays a role in Republican primary races, said he welcomed a pragmatic sense of discipline in recruiting candidates. But he said it was incorrect to suggest that candidates backed by Tea Party groups were the only ones to lose, pointing to establishment Republicans in North Dakota and Montana who also lost their races last year.
"People are imagining a problem that doesn't exist," Mr. Norquist said. "We've had people challenge the establishment guy and do swimmingly."
Sue Everhart, the head of the Georgia Republican Party, said she did not object to outside intervention. But because open Senate seats do not come along very often, she said,"we have six congressmen who want the job," which could create a messy and divisive primary regardless of the efforts to control the race.
"The primary has to sort itself out in Georgia," Ms. Everhart said. "That's what primaries are for. But we cannot afford to take our eye off the ball. This is going to be a very important election, and it's paramount that Georgia keeps its Senate seat in Republican hands."
This article originally appeared in The New York Times.