WASHINGTON — Austin Mayor Steve Adler traveled more than 1,000 miles to endorse Pete Buttigieg for president.

“Wouldn’t it be great if we had a president who was smart? Like really, really smart?” Adler asked the crowd packed into a former Studebaker factory in South Bend, Indiana, Sunday.

Those words must have landed hard with the two Texans who are seeking the presidency, former Rep. Beto O'Rourke and former Housing and Urban Development Secretary Julian Castro. But they did get consolation prizes from the mayor of their home-state's famously liberal capital city: like Buttigieg, they got campaign checks from Adler.

“I like those three guys," Adler said in a phone interview. "I’ve endorsed Buttigieg, but I think that all three of those guys are really good and strong, and I wanted them all to be part of the discussion.”

“I am excited for each of their voices to be heard," he added. "I think that is important. The debates will be really exciting and really constructive for the country.”

At a time when most Democrats are certain that they want to nominate the candidate most likely to beat President Donald Trump — and equally uncertain who that candidate is — Adler is just one of hundreds upon hundreds of donors who are putting their money behind more than one horse.

More than 1,500 people donated at least $200 apiece to multiple Democratic presidential candidates in the first three months of 2019, according to an NBC News analysis of Federal Election Commission filings. Candidates are only required to report the names of contributors who give them $200 or more, meaning the total number of such "crossover" donors could be far higher.

California Sen. Kamala Harris, D-Calif., had the largest number of crossover donors. Out of her 7,533 unique donors, at least 663 also gave to one or more of the other candidates. Buttigieg came in second, with 448 crossover donors out of his 4,042 unique donors.

The biggest crossover among candidates was between Harris and Buttigieg — at least 162 donors gave to both of their campaigns. Additionally, 142 gave to Harris and Sen. Cory Booker of New Jersey; 132 to Buttigieg and O’Rourke; and 128 to Harris and Sen. Amy Klobuchar of Minnesota.

The primary season debates may be playing a role in the decision-making process: In interviews with NBC News, many donors echoed Adler’s motivation, saying that their goal was to make sure a diverse range of candidates qualified for a spot on stage. (The Democratic National Committee requires a candidate to reach 1 percent in at least three national or early primary state polls, or to raise money from 65,000 donors in at least 20 different states to claim a podium.)

For Seth Rosen, a New York attorney and fundraiser for the National LGBT Bar Association, that means donating to candidates who represent groups who have historically been underrepresented and underfunded. So far, Rosen has given money to Buttigieg, Harris and Sen. Kirsten Gillibrand of New York.

“Quite frankly, I am only supporting women, queer people and people of color in the primary,” Rosen said in a phone interview, adding that he would ultimately throw his financial support behind whoever wins the nomination. “I am a gay man who is married to my husband and we have two black kids, and I want to make sure that we see aspects of our family reflected on the debate stage.”

Mark Alfano, an Oregon native and a philosophy professor at Australian Catholic University, said that he gave to Sen. Elizabeth Warren of Massachusetts and Sen. Bernie Sanders of Vermont because he most strongly agrees with their positions and hopes one of them will eventually secure the nomination.

But he also gave money to Buttigieg "because there was a question about if he would be included in the debates and polls, and I wanted him to reach that threshold,” Alfano said. “I think that Buttigieg represents a voice from communities that have long been neglected by the Democratic Party.”

Alfano, an expert in behavioral science, said that he did not view giving money to competing candidates as counterproductive or irrational.

“Actually, I think that the first-past-the-post voting system is the real problem," he said. "While many of us can’t rank our choices in the primaries, we can sort of do that indirectly through our donations."

For some high-dollar Democratic donors who are used to being courted by presidential hopefuls, the decision to give to several candidates is about more than just helping some get to the debate stage. It’s personal.

“My thought is, unlike 2008, when for the most part it was a three person race between Barack Obama, Hillary Clinton and John Edwards, this is a much deeper slate of candidates,” said Robert Wolf, a long-time Democratic donor who has already given to five campaigns. “And you know, I myself and many staunch Democrats have people they have known for a very long time running,” he added, noting that he has sat down personally with a handful of the primary candidates already.

This personal dynamic between 2020 candidates and big donors is not surprising, said Rufus Gifford, who oversaw fundraising for Obama’s 2012 re-election campaign and has also given to multiple campaigns so far this cycle.

“Considering the uniqueness of this race, the donor class will have relationships with so many of these senators and governors who have been around for a long time,” Gifford said in a phone interview. “A lot of us believe in more than one candidate, so we may not be picking the horse right now.”

Several big Democratic donors who spoke to NBC News said they recognized the uniqueness of this campaign, saying it was an indication of just how wide open the field is, as opposed to past races that featured two or three candidates who ran far ahead of the pack.

But even though donors are able to spread their resources among a handful of candidates for now, some worry the trend may spread the party too thin and hinder the eventual nominee's chances in the general election.

Democratic candidates collectively brought in roughly $75 million in the first quarter of 2019. At this point in the 2008 presidential cycle, Democratic candidates had collectively raised $80 million — a comparison that only looks worse when considering inflation, the state of the economy, changes to campaign finance law that have since raised the maximum donation amount, and technological changes that have made it easier than ever to donate electronically.

Gifford also pointed to the reluctance among some candidates to actively woo big-money donors. “I think that there's been a level of financial purity among the candidates in not wanting to engage folks who have been traditional funders, and I think that's a big mistake," he said. "We need all the resources at our disposal.”

When stacked against the whopping $30 million that President Donald Trump’s re-election campaign raised in the first quarter, some Democrats worry that by the time the party has coalesced around a front-runner, that nominee could be left playing campaign cash catch-up.

“For me, I am very concerned about the low fundraising numbers for the Democratic candidates," Gifford said. "The stakes are far too high for us.”