Coming off an overwhelming victory for Donald Trump in New York, the field has narrowed considerably. With only one other barely viable candidate in Texas Sen. Ted Cruz, a quixotic campaign from Ohio Gov. John Kasich, and an anti-Donald Trump movement, a number of top donors -- and their millions of dollars -- who have seen their chosen candidate or candidates drop out of the race are still waiting on the sidelines, unconvinced that any of the remaining options is worth their investment.
"I think a lot of people are where I am, which is basically -- it's gotten cloudy and misty and we can't really tell what's going on. We know what's going on in the battlefield, but we don't feel like we can affect it very much," said Frank VanderSloot, a billionaire Idaho businessman who gave millions to Mitt Romney's presidential campaign and supported Florida Sen. Marco Rubio in this year's race. "I know enough people to know that I'm not alone in this."
Major donors that have previously supported Republicans that are sitting on the sidelines right now include VanderSloot; billionaire Vegas casino mogul Sheldon Adelson, who hasn't played in the primary after spending $100 million last cycle; energy mogul T. Boone Pickens, whose spokesman says he'll back an eventual nominee after supporting former Florida Gov. Jeb Bush, Ben Carson and Carly Fiorina; health industry billionaire Mike Fernandez, who gave millions to Romney and Bush but whose spokeswoman said is stepping back from politics; and businessman and former politician Art Pope, a former Rubio donor who has put millions into North Carolina politics and is connected to the Koch brothers' money network.
The Trump effect may be most responsible for keeping big money on the sidelines. Donors have seen their money go to waste as Trump continued to rise in the polls, and some remain unconvinced more spending can slow him down.
"There's a certain degree to which Donald Trump has left people sort of shell-shocked," said GOP strategist Rick Wilson, who formed a super PAC that backed Rubio.
Yet many in the donor class see problems with all of their options. Cruz, who has a powerful fundraising machine, has been actively reaching out to new benefactors. But many of the donors who backed his opponents, or didn't support anyone, are slow to join his side. They're concerned about his ability to win a general election, seeing him as too stalwart and too conservative to convince the American people.
"He's had lots of chances to prove he can work with others and so forth, but in the Senate he's worked as an island and he apparently doesn't have the ability to work with other people," VanderSloot said. "That doesn't make for a good leader. ... I'd worry he can even win the general."
Meanwhile, donors haven't flooded Kasich's campaign as it is mathematically impossible for him to clinch the nomination outside of a contested convention. And Trump has waged war on the Republican Party establishment and bragged about not accepting donor cash.
Katie Packer, Romney's former deputy campaign manager who is now running an anti-Trump super PAC, said some people are "still licking their wounds" from the cycle.
But she added said that people won't back a strategy if they don't see it having a chance of winning.
"A lot of donors are risk averse by nature," Packer said. "That's how they've become very successful, and so if they can't see a clear path, they're not going to invest in it. And this cycle, there's no clear path. Everything is going to be kind of hand-to-hand combat."
Rubio's former finance chairman, lobbyist Wayne Berman, called it a general "weariness" among people who have backed sometimes two or three candidates already and may be recovering from that emotional and financial investment.
And it's hard to get motivated with diminishing returns, said major Republican bundler Dave Tamasi, who raised money for Romney, Chris Christie and Rubio before deciding to wait out the rest of the primary. He added any effort right now would be likely someone's third or fourth choice -- hardly a draw for an exhaustive campaign.
"Your guy loses in a year where it almost feels like you're not sure what you could have done to win, so the idea of getting back on another horse that wasn't your first love to begin with isn't very attractive," Tamasi said. In the current field, "there's no certainty. When you put all those things together, people don't necessarily see any upside to starting all over this late in the process to getting involved."
Wilson pointed to the failed Bush campaign, which was backed by more than $100 million, as a warning.
"The other thing that's left people shell-shocked is Right to Rise, which took in a giant pile of money and their (return on investment) for these donors, these people who wrote millions of dollars of checks, is zero," Wilson said. "When Jeb wrote ads, one of two things happened: his numbers went down, or nothing happened."
"People are not looking to necessarily throw good money after bad," Tamasi said. "The anti-Trump efforts got off the ground too late in the process to be fully realized."
When will donors commit?
Pope said he is keeping his options open to the point that he may run as a delegate from North Carolina supporting Rubio, giving him a front-row seat for the action at a potentially contested convention.
And he won't commit to supporting an eventual nominee no matter what.
"I have never pledged to automatically support a Republican nominee regardless of who that nominee is, I am not going to change that position in this point in time," Pope said.
VanderSloot predicted the money will continue to sit out until there's a path forward to stopping Trump, whom he called a "potential disaster," and finding a winning candidate.
"There's a lot of money on the sidelines, I think it's staying there. I think it's going to stay on the sidelines, I don't think people are going to put money in because nothing's changed, we don't see a clear front-runner," he said. "You might see some money coalesce around whatever the strategy might be to avoid having Donald Trump as our nominee."
Wilson said he would advise donors to develop a multi-tier contingency plan to stop Trump, which would include first forcing a contested convention, then finding a plausible conservative who could run at the convention and pick up the nomination. If that fails, he said, he'd consider backing a third-party conservative who could pick up enough electoral college votes to prevent anyone from getting a majority, sending the election to the GOP-controlled House of Representatives.
And yes, he acknowledged the idea was far-fetched, but it speaks to the GOP angst, he said.
"Yes, I'm talking about ridiculous absurdities that no person should have to be talking about at this day and age. But the party has gone off the rails and it's so wacky and you have to play these games now," Wilson said.