Tesla CEO Elon Musk endorsed Donald Trump for president after the failed assassination attempt against Trump on July 13. That may not do much for Trump.

Political candidates crave the backing of billionaires like Musk, especially if they open their wallets and fund campaign activities. Billionaires love to put their thumbs on the political scales by throwing their money around, influencing their candidates of choice, and calling in favors after their horse wins.

Except billionaires don’t always get their way. Not in politics, anyhow. In fact, a shrewd candidate running against the billionaires' pick can position himself as the everyman fighting the moneyed interests.

Trump has been enjoying a billionaire bonanza during the last couple of months. In addition to Musk, the world’s richest man, hedge-fund magnate Bill Ackman endorsed Trump after the assassination attempt, and billionaire investors Ken Griffin of Citadel and Paul Singer of Elliott Management seem to be lining up behind Trump.

Other rich Trump backers include Steve Schwarzman, CEO of the Blackstone Group, and casino baroness Miriam Adelson. Banking heir Tim Mellon gave a Trump political action committee $50 million after a New York jury convicted Trump on 34 counts of business fraud in May. The five biggest donors to political committees this election cycle have given $309 million to Republicans and essentially nothing to Democrats.

But rich donors often get a poor return on their political investments. They can give millions to so-called super PACs that operate on behalf of a given candidate by running ads or trashing the opponent, but there are limits on what they can donate to the campaign itself. More important for a presidential campaign is the number of small donors who send in money up to the legal limit, which for 2024 is $3,300 per donor.

The 2012 presidential election is instructive. Republican Mitt Romney enjoyed the backing of the biggest donor that year, Sheldon Adelson, who, along with his wife Miriam, gave $93 million to Republican causes. (Sheldon Adelson died in 2021.) Wealthy donors backing Romney contributed $145 million, while wealthy donors backing Obama gave just $75 million. Yet Obama outraised Romney among small donors, $739 million to $483 million. Obama swamped Romney that November, winning 332 electoral votes.

In 2016, the big money initially backed the now-forgotten Jeb Bush, who drew $244 million in outside funding, only to lose the Republican primary to Trump. In the general election, Democrat Hillary Clinton raised more than twice as much outside funding as Trump, with $412 million to just $201 million for Trump. Yet Trump won.

In 2020, Biden outraised Trump among big donors, $580 million to $313 million. That was the first time in three election cycles that the candidate with the most big-money backing actually won. Some of the big Democratic contributors in 2020, such as former New York mayor Michael Bloomberg and the investor Tom Steyer, may very well back Dems again in 2024, offsetting Trump’s current billionaire edge.

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Aside from money, it’s not clear a recommendation from 1 percenters has any effect on the votes of ordinary people. Musk, who does not typically donate to political campaigns, has seemingly become less popular as he has become more outspoken and political. Consumer interest in Tesla automobiles has plummeted since 2021, a time span that includes Musk’s purchase of Twitter and a litany of provocative statements and actions. One bumper sticker some Tesla owners display reads, “I bought this before we knew Elon was crazy.”

Musk has demonstrated Trumpy leanings since he strongly resisted mask mandates during the 2020 COVID outbreak. His fans are Trumpy by nature, so it’s not clear any voter who’s on the fence in this year’s election would be swayed by anything Musk says.

Many of Trump’s other billionaire backers, meanwhile, are hoping for the lower taxes and lighter regulatory touch Trump promises. Biden, by contrast, wants to raise taxes on everybody earning more than $400,000 per year. So Biden can plausibly tell voters that billionaires backing Trump are simply doing so out of self-interest, hoping for a smaller tax bill and other perks should Trump win.

The billionaire effect is weak in presidential elections when the candidate they’re trying to take down has a strong bond with ordinary voters. Obama had that in 2012. Trump surprised everybody in 2016 by establishing a populist appeal that eluded other candidates.

Joe Biden in 2024 may be lacking that. The 81-year-old Biden is struggling to maintain his standing even with supporters, who worry that he’s too old and frail for another four years in the White House. A teetering incumbent may be more vulnerable to the onslaught of attack ads and mudslinging that billionaires can finance through mega donations to super PACs. If so, Biden will be blowing the chance to turn Trump’s appeal to billionaires to his own advantage.

Rick Newman is a senior columnist for Yahoo Finance. Follow him on Twitter at @rickjnewman.

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