Veteran Republican fundraisers are increasingly alarmed by the defiant stance of hard-line conservatives amid the federal government shutdown, prompting fears that many key donors may be restrained in their giving going into the 2014 midterms.

The growing unhappiness among longtime GOP check-writers and party elders underscores the deepening divisions over the ascendant tea party wing, which fueled this past week’s shutdown and is demanding Democratic concessions in exchange for reopening the government and raising the nation’s debt limit.

The tensions bubbled up this past week at a three-day gathering in Washington for backers of American Crossroads and Crossroads GPS, the GOP-allied groups founded with the help of strategist Karl Rove that pumped hundreds of millions of dollars into the past two elections.

In between private sessions at the Four Seasons hotel with GOP stars such as Louisiana Gov. Bobby Jindal, Sen. Rand Paul of Kentucky and Sen. Marco Rubio of Florida, many attendees expressed concern about the strategy of tying funding of the government to measures that would stymie the president’s health-insurance initiative.

“People are totally annoyed,” said one attendee at the Crossroads meeting who asked not to be identified, to discuss private conversations.

Chris Cillizza shares three things about the government shutdown that we've learned this week. (The Washington Post)

The frustration was evident this past week not just at the Crossroads conference but also throughout the party’s high-end donor class. While grass-roots activists cheer the unyielding positions of conservative House Republicans, some of the GOP’s top fundraisers are watching the situation with growing dismay.

“I oppose Obamacare as much as anyone else does, but this is not the way to repeal it,” said Bobbie Kilberg, a longtime GOP donor and fundraiser in Northern Virginia.

“The fact is, donors have had it,” Kilberg added, saying she will not give donations to groups raising money broadly for House or Senate Republicans. “I will only give to individual candidates who get it.”

It is too early to tell whether the discontent will seriously hamper fundraising for party committees and independent groups such as Crossroads. Some top GOP fundraisers said they think donors upset with the strategy will still write checks in the end.

“They don’t think that shutting down the government is good for the country,” said Fred Malek, a prominent GOP financier. “But by the same token, it doesn’t appear to impact their resolve to be competitive in each and every race next year.”

Other elder statesmen are more apprehensive. “There are a lot of liabilities with this approach,” said Vin Weber, a former Minnesota congressman who sits on the board of the American Action Network, which spent more than $11 million on independent expenditures in the 2012 elections. “To portray Republicans as universally cheering the shutdown is a mistake,” he said. “Not all of our donors are activist tea party people. Some are, but they are a vocal minority.”

The shutdown is playing out during a key fundraising period for party committees and independent advocacy groups, which are drawing up plans for their 2014 campaigns.

Republicans set ambitious goals after the party’s defeat in the 2012 presidential election amid broad acknowledgment that the party had fallen behind Democrats in harnessing technology and data to reach voters.

The two Crossroads organizations together raised more than $300 million in the 2012 cycle. But as expected in a post-election year, revenue declined in the first six months of 2013. The groups brought in just $3.3 million, including $1 million from Contran Corp., the holding company of Dallas billionaire Harold Simmons.

One top party fundraiser said the Wall Street financiers and corporate executives he counts on for support are “having fits” over the GOP’s brinkmanship strategy, especially related to a potential default if Congress does not agree to raise the debt ceiling later this month.

“The donors I raise money from understand the vital importance of credit markets and are upset that the U.S. credit system is being put at risk,” said the fundraiser, who requested anonymity because of his position in the business world.

Many veteran GOP donors also take a particularly dim view of freshman Sen. Ted Cruz of Texas, a tea party favorite who helped lead the shutdown strategy.

“It appears that we’ve got a bunch of crazies running around — one from Texas and some from other places,” said Al Hoffman Jr., a former Republican National Committee finance chairman and a top fundraiser in Florida. “I love the idea of defunding Obamacare. However, I don’t think it’s going to happen until we have a majority in the Senate and in the House.”

“There are a lot of major donors who feel that until the Republican party can field people who have a vested opinion of what to do and to do it in a prompt and efficient way, we’re going to withhold giving money,” Hoffman said, adding that the donor freeze could affect “a lot of current far-right Republicans.”

Other major financiers, however, admire leaders such as Cruz. On Tuesday night, he received a warm reception at a private dinner held at the Willard hotel for about 50 top RNC donors who were in Washington for the party’s quarterly meeting.

Ray Washburne, a Dallas investor who serves as national finance chairman, said he was struck by how donors responded to Cruz.

“There’s no secret he’s a lightning rod,” Washburne said. “But let me tell you — they took to him, that someone is standing up for their principles and not wavering.”

Some of the groups that support tea party lawmakers also report strong fundraising in recent weeks as the push to defund Obamacare or shut down the government gained steam.

The Senate Conservatives Fund raised $1.5 million in August from donors giving an average of $45, according to Matt Hoskins, the group’s executive director. The group, which is closely aligned with Cruz and has primarily targeted Republican lawmakers with attack ads, expects to report higher revenue in September, Hoskins said.

He scoffed at criticism from longtime GOP fundraisers, calling them “wealthy donors who like to go to fancy cocktail parties and don’t speak for the grass roots.”