Updated

Influential Republicans pledged Wednesday to support Christine O'Donnell's general election campaign after party leaders initially turned their backs on the Tea Party candidate following her upset win in the Delaware Senate primary.

O'Donnell's rise from obscurity to victory over longtime Rep. Mike Castle had sent Republican honchos in Delaware and Washington into a state of political shock. Aides for the top fundraising arm for Senate Republicans said Tuesday she would not be getting help from them -- a reaction that raised concern the party would torpedo its chances at a congressional takeover out of spite.

But National Republican Senatorial Committee Chairman John Cornyn said in a written statement Wednesday that O'Donnell would have NRSC support as well as the maximum $42,000 donation from the organization.

"Let there be no mistake: The National Republican Senatorial Committee -- and I personally as the committee's chairman -- strongly stand by all of our Republican nominees, including Christine O'Donnell in Delaware," Cornyn said.

Castle, who argued O'Donnell could not win in a general election against Democrat Chris Coons, reportedly will not endorse O'Donnell. But party leaders on Capitol Hill tried to embrace her candidacy Wednesday.

More On This...

Senate Minority Leader Mitch McConnell, R-Ky., told Fox News he would support the nominee and donate money from his political action committee.

Republican National Committee Chairman Michael Steele announced his support.

Rep. Mike Pence, R-Ind., the third-ranking Republican in the House, said he would not count out O'Donnell in November.

"I categorically reject that Christine O'Donnell cannot win in Delaware," he said. "This is a whole new world. We elected a Republican in Massachusetts."

O'Donnell's win posed one of the biggest upsets to the Republican establishment this year -- a campaign season marked by a series of outsider Tea Party victories. Republican leaders ultimately came around to candidates like Sharron Angle in the Nevada Senate race and Joe Miller in the Alaska Senate race, where incumbent Sen. Lisa Murkowski was defeated in the primary last month and has not yet decided her next move. Cornyn pointed out Wednesday that the NRSC also just aired its first ad in support of GOP Senate nominee Rand Paul, a Tea Party favorite, in Kentucky.

O'Donnell, though, was a perennial candidate with no government experience and a history of personal financial problems. Delaware Republican leaders had condemned her candidacy and offered few words of encouragement after her victory over Castle by a 6-point margin.

Republican strategist Brad Blakeman said the initial move to alienate O'Donnell was poor strategy for Republicans looking to take over at least one chamber of Congress in the fall. He said the party needs to unite with all the Tea Party-backed nominees before November or risk not only losing seats but the possibility of the Tea Party defecting into a bona fide third party.

"We're not going to like every candidate 100 percent," Blakeman said. "You need to regroup now. ... The risk is you're going to blow apart the Republican Party."

Democrats sought to exploit any sign of division over the O'Donnell win. House Majority Leader Steny Hoyer said Wednesday that Tea Party candidates like O'Donnell will hurt Republicans in the fall.

"Republicans in Delaware nominated somebody that they don't believe can win -- I think, in the words of the state party chair, couldn't be elected dogcatcher," White House Press Secretary Robert Gibbs said Wednesday.

Long-distance disputes between O'Donnell and her supporters and prominent Republicans continued into Wednesday, though party leaders began to embrace her.

Former Bush administration adviser Karl Rove, a Fox News contributor, had criticized O'Donnell's candidacy Tuesday night. O'Donnell, in an interview with Fox News Wednesday morning said Rove's "credibility" had been damaged by her victory.

Asked about the tiff, Rove said Wednesday that his problems with O'Donnell concern her "character" and "background," not her ideology.

"If she wins, more power to her -- she's right on the issues," he said. "She's got to answer these troubling questions."

Former Alaska Gov. Sarah Palin, who gave O'Donnell a boost in profile by endorsing her in the final days of the campaign, said Republicans need to close ranks now that the primaries are over.

"Those who say that the GOP nominee is not elect-able or that they're not even going to try, well I say buck up," Palin told Fox News. "I have absolutely nothing against Karl Rove. ... They need to realize that the time for primary debate now is obviously over and it's time for unity."