WASHINGTON — Primary victories for GOP senatorial contenders Christine O’Donnell of Delaware and Kelly Ayotte, New Hampshire’s attorney general, boosted hopes that the 2010 midterm elections will make this “the year of the pro-life woman,” particularly in the Senate.

But O’Donnell’s win also exposed long-simmering tensions within the Republican Party, pitting its leadership against Tea Party activists. The GOP appears poised to sideline life issues in its effort to retake the Senate by appealing primarily to voters’ concerns about the economy, government overreach and unemployment.

The divided reaction to O’Donnell’s triumph underscored competing objectives within the party. While pro-life leaders and Republican National Committee Chairman Michael Steele embraced O’Donnell, top party strategist Karl Rove and the National Republican Senatorial Committee distanced the GOP from her campaign.

“Christine O’Donnell’s win, combined with the successes of Carly Fiorina and Sharron Angle, continues building momentum for 2010 to be remembered as the ‘Year of the Pro-Life Woman,’” said Susan B. Anthony List’s president, Marjorie Dannenfelser, in a statement released after the Delaware primary results were broadcast.

“While her primary opponent held an explicitly pro-abortion voting record, O’Donnell expressed her strong determination to be a vocal advocate for women and unborn children on the floor of the U.S. Senate, a stance which clearly made a difference at the ballot box,” continued Dannenfelser.

But Rove offered a sharply different judgment on Fox News, where he distanced the GOP from O’Donnell, questioning her “rectitude and truthfulness and sincerity.” Rove added, “We were looking at eight to nine seats in the Senate; we’re now looking at seven to eight.”

Dubbed “tropical storm Karl Rove,” the broadside fueled a frenzy of intra-party debate regarding the wisdom of publicly attacking a GOP candidate. Rove’s defenders speculated that he sought to deflect Democratic efforts to make O’Donnell — an inexperienced politician with a checkered personal history — the public “face” of the GOP.

Indeed, White House spokesman Robert Gibbs quickly jumped into the debate, suggesting that the firestorm signaled substantive problems with O’Donnell’s candidacy, as well as a lack of GOP unity. As if to prove him wrong, National Republican Senatorial Committee Chairman John Cornyn promised to provide funds for O’Donnell’s campaign — reportedly a reversal of the committee’s previous stance.

Some conservatives back Rove’s central point: O’Donnell’s candidacy short-circuited the party’s mission to re-take the Senate. National Review Online’s Jim Geraghty suggested conservatives should have backed the safe bet in the Republican primary: Rep. Mike Castle, a liberal Republican, would likely vote with them “52% of the time.”

Geraghty noted that the congressman “supported an amendment to the health-care bill that would ban using taxpayer funds to provide abortion services, an interesting vote for a self-described pro-choice Republican. He voted against the health-care bill.”

The SBA List’s Dannenfelser defended her organization’s endorsement of O’Donnell, a pro-life activist and chastity educator. “Here’s how we approached this midterm election: There was a strong wind blowing for a different type of candidate. Women who had not appeared viable in other elections were starting to become viable,” she said in an interview.

Asked if the SBA List delved into O’Donnell’s personal history, Dannenfelser said, “We interviewed her; there was a rigorous questionnaire. But there were late-breaking issues — those don’t come out early in the process.”

The subtext of the dispute regarding O’Donnell, say some observers, is the perceived viability of social issues in a midterm election widely viewed as a referendum on President Obama’s economic policies.

“Fiscal issues have been primary in most people’s minds and in the media,” acknowledged Tom McClusky, vice president for government affairs of the Family Research Council, which also endorsed O’Donnell. “But when you look at the nuts and bolts of the primary campaigns, life issues have been foremost.”

“In Alaska, Joe Miller’s win was attributed to his all-out support for parental notification — unlike [Lisa] Murkowski, his opponent in the primary. Angle, Marco Rubio, the Florida Senate candidate, and Nikki Haley, the candidate for governor of South Carolina, have all embraced social issues,” said McClusky.

Focusing on strategic party goals while affirming the conservative principles that drive the party’s base has been a tough balancing act for GOP leaders ever since “Reagan Democrats” altered the GOP’s political composition in the 1980s. Sarah Palin, another unpredictable force in the party, backed O’Donnell.

This year, the rise of the Tea Party movement, a grassroots initiative that includes libertarians and social conservatives, has further complicated the work of the National Republican Senatorial Committee: Sens. Bob Bennett of Utah and Murkowski of Alaska were among the eight establishment candidates who lost their primaries this year.

In past years, the collision between short-term political tactics and conservative principles has brought down top pro-life leaders like Sen. Rick Santorum of Pennsylvania. He lost his 2006 Senate race in part because pro-lifers — angry about his previous endorsement of Sen. Arlen Specter — refused to work for his re-election.

That same anger was on display last month as conservative commentators took pot shots at the GOP leadership.

“Those who believe the [William F.] Buckley rule, that conservatives should vote for the ‘rightward-most viable candidate,’ know that the party establishment rarely followed it. If it had, it might have been taken seriously when addressing O’Donnell’s shortcomings,” charged J.P. Freire in the Washington Examiner.

The Family Research Council’s McClusky takes a cooler view, but he agrees that the GOP leadership has stumbled when backing candidates like Florida’s Charlie Crist and Rhode Island’s Lincoln Chafee, who failed to win Republican Senate primaries.

“If he won, Mike Castle would have been the next Arlen Specter or the next Jim Jeffords [senators who switched political parties],” said McClusky, who has spoken before Tea Party groups and says they are open to life issues.

Brian Burch, president of CatholicVote.org, an online movement of lay Catholics involved in issue advocacy and electoral politics that reports about 550,000 members, says the Tea Party movement includes many “independent Catholics” frustrated with the political status quo.

“It’s no secret that, for the sake of winning seats, the northeast Republican leadership has been willing to compromise the party platform, which has been pro-life,” said Burch.

“In the past, Christine O’Donnell would have lost,” he added. “She won with the support and passion of the Tea Party movement, a bipartisan movement that includes Catholic independents.”

With midterm elections fast approaching, some Republican leaders may still be on the fence about O’Donnell, but they’re scrambling to shore up their credibility with the party’s base, including the Tea Party newcomers.

Within days of his broadside against O’Donnell, Rove returned to Fox News to defend his position.

Yet he insisted that his recent actions had actually “helped,” not hurt O’Donnell: Her angry supporters would retaliate against him, he predicted, by pouring money into her campaign coffers.

Joan Frawley Desmond writes from Chevy Chase, Maryland.