The Republican donors who helped Mitt Romney raise $1 billion in 2012 have a target figure in mind for Donald Trump: zero.

Repelled by Trump and convinced he can't beat Hillary Clinton, wealthy GOP contributors are abandoning the presidential contest and directing their lucrative networks to spend to invest in protecting vulnerable Republican majorities in the House and Senate.

They are undoubtedly gun shy after wasting time and money on Republicans who Trump destroyed in the primary. They raised untold millions for more than a dozen top flight candidates, and wrote big personal checks to their super PACs.

But on policy and fitness for the presidency, the party's most active contributors and bundlers simply can't bring themselves to support their front-runner, reluctantly preferring a Clinton administration that is checked by a GOP congress.

"There's a significant segment of large donors, and the donor community at large, that would need to see a fundamentally different approach to raise money, or give money, to Trump," Fred Malek, a veteran GOP bundler and the Republican Governors Association finance chairman, told the Washington Examiner.

What might Republican donors need to see out of Trump to soften their opposition? "A more tolerant, inclusive candidate that acts more like what they think a president should be like," Malek said.

Trump, a New York real estate developer and reality television star, claims a net worth of $10 billion. He loaned his campaign just under $36 million that is eligible to be paid back with contributions. It was a minuscule investment, relative to Trump's GOP competition, and worked in part because of his dominating presence on cable television news and social media.

Competing in the general election against Clinton, the likely Democratic nominee, is expected to cost quite a bit more, and Trump has signaled that he would raise money to pay for it. Clinton could raise around $2 billion for her campaign, and it's unclear that Trump is liquid enough to fund a national campaign that can keep pace.

Small donations from grassroots contributors constitute one avenue for Trump to pursue. He has accepted more than $12 million in such money so far. It might be his only option. Republican fundraisers and bundlers are unlikely to give to Trump after he spent months demonizing them as corrupt operators whose only interest is buying off politicians.

"If I'm a donor, why would I give to someone who claims that the only reason I give is to get something?" said Lisa Spies, a Republican fundraising consultant in Washington who advised Romney in 2012, and this cycle raised money for Jeb Bush. "If Trump is as wealthy as he says he is, he can fund his own campaign."

Trump has another problem.

The businessman hasn't put in the time and effort to court donors. In interviews with the Examiner on Tuesday, as Trump was beating Sen. Ted Cruz of Texas in Indiana and moving closer to capturing the nomination, Republican donors and bundlers said that they've never heard from a Trump representative.

Federal law limits what individuals can give to a presidential campaign; this cycle, that figure is $2,700 in the primary and an equal amount in the general election. Cultivating a national donor network that can effectively bundle hundreds of millions of dollars requires strong relationship and takes time — sometimes years.

Even if Trump wanted to make nice with GOP moneymen, there's insufficient time to establish a presidential-level finance operation.

"They can't even run a delegate operation, much less a donor network," said a Republican strategist, who requested anonymity in order to speak candidly. "The time to start that was two years ago. You can't make friends fast in politics."

Wealthy Republican donors are typically successful business people who approach politics pragmatically. They tend to support candidates most likely to win, with less regard to ideology, often to the chagrin of committed conservative activists. So in many ways it's unusual that establishment contributors in New York, Washington and around the country aren't preparing to open their wallets to Trump, now that he appears more likely to be the nominee.

But their issues with him are twofold.

On the issues, Trump's populism bothers donors, who tend to support the GOP because it has been the party of free markets, free trade, and lately, shrinking the size and scope of government through reforming Medicare and Social Security. On foreign policy, they prefer robust U.S. leadership abroad, making Clinton a preferable commander in chief when measured against Trump's isolationism.

Then there's Trump's behavior. Republican donors see a U.S. that is evolving demographically and becoming less white. Trump's harsh rhetoric directed toward illegal Mexican immigrants and Muslims, and long history of publicly insulting women and his critics, leads them to believe he will inflict long-term damage to the GOP, and worse, that he is unfit for the presidency.

Given their options, Republican donors prefer Clinton in the White House and Republicans controlling the House and Senate.

Indeed, Spies said that she recently organized an event to raise money for Sens. Kelly Ayotte, R-N.H.; Roy Blunt, R-Mo.; Ron Johnson, R-Wis.; and Rob Portman, R-Ohio; as well as House Foreign Affairs Chairman Ed Royce, R-Calif., that was supported by bundlers who would normally be too busy focused on the presidential race to be bothered with down ballot candidates.

"People are very concerned about what a Trump presidency would mean," said a GOP bundler with relationships in New York. "I think people are going to salvage what they can and try and rebuild things after November."