Democratic presidential hopefuls from outside of Texas are ringing up the Lone Star State for campaign cash, already raising hundreds of thousands of dollars in a state that could prove to be pivotal in the 2020 election.

And if dollars end up equaling delegates in next year’s high-stakes primary, then native sons Beto O’Rourke and Julián Castro are on notice.

The former El Paso congressman and the former U.S housing secretary remain formidable foes in their home state, particularly after O’Rourke quickly brought in $2.1 million from Texas through the end of March and Castro raised $420,000 there during that time.

But others have also found early fundraising success in Texas, demonstrating their ability to siphon off support in a delegate-rich state that’s now forward on the primary calendar.

Six non-Texan contenders have so far brought in more than $100,000 from Texas: California Sen. Kamala Harris, New York Sen. Kirsten Gillibrand, Minnesota Sen. Amy Klobuchar, Vermont Sen. Bernie Sanders, New Jersey Sen. Cory Booker and Indiana mayor Pete Buttigieg.

That battle is likely to only intensify now that former Vice President Joe Biden — described by one Texas donor as the "donkey in the room" — has announced a bid for the White House.

"It's going to be a contested, tough race in Texas," said Domingo Garcia, the national president of the League of United Latin American Citizens and a Dallas politico who's donated so far to Sanders, Castro and Warren. "Both Beto and Julián are going to have to work at it."

Success with donors big and small, of course, does not necessarily translate to a bonanza at the ballot box — in Texas or anywhere else. Otherwise, Democrat Hillary Clinton or Republican Jeb Bush would now reside in the White House instead of President Donald Trump.

Texas also offers something of an unusual case for a Democratic presidential race.

Many liberal donors have almost been trained to back White House contenders from farther afield, if for no other reason than that Texas has not produced a legit home-state presidential candidate since Lloyd Bentsen in 1976. So this cycle’s experience, for many, is altogether new.

But fundraising prowess, particularly in Texas, is nevertheless a crucial metric.

It spotlights influence, organization and, perhaps most important, viability in a 20-candidate Democratic contest that will require the resources to survive a race that remains more than nine months away from the earliest primaries.

Of particular note in the early Texas fundraising data is the strength of Harris, Klobuchar and Gillibrand, three women whose performances highlight how the most diverse Democratic presidential field ever could produce a commander in chief who breaks the mold.

“A woman, like a man, who makes the case for why we need change and who talks about the issues that Texans care about ... they have a great opportunity to secure support across the state,” said Patsy Woods Martin, a Gillibrand donor who’s worked to elect women to office in Texas.

Texas has long been a reliable political ATM for national Democrats, even with the state's standing as a GOP stronghold.

The Lone Star State provided Clinton, for instance, more campaign cash in 2016 than any other state except California and New York, according to the Center for Responsive Politics. The state was similarly prolific for former President Barack Obama in his two White House runs.

Presidential candidate Julián Castro relies on the fundraising base of his native San Antonio, where the former U.S. housing secretary served as mayor.. (Eric Gay / The Associated Press)

To get an early look at the state of play for 2020, The Dallas Morning News analyzed first-quarter campaign finance reports filed this month with the Federal Election Commission.

The data is imperfect — particularly when it comes to geography — thanks to how some candidates tallied their hauls and how some small-dollar donations are not reported with detailed information on a donor’s name, address and profession.

What’s nonetheless clear is that O’Rourke and Castro continue to benefit from favored son status.

Both Texans count their home state as their top fundraising source, even as they’ve devoted most of their time on the stump to other primary states. The fruits of O’Rourke’s record-smashing $80 million Senate campaign last year against Sen. Ted Cruz are most obvious.

While Castro’s base is centered on his native San Antonio — where he served as mayor — O’Rourke has high-dollar footholds all across Texas.

Strong fundraising at home could point to eventual primary success there, which would be vital now that Texas has moved up the calendar to Super Tuesday in early March. But Texas is not winner-take-all, meaning other Democrats will have ample opportunity to peel away delegates.

If early donors offer a guide in Texas, then the state is not a foregone conclusion.

“It appears to me that donors are certainly supporting those two candidates, but also looking at some of the other ones,” said Marc Stanley, a Dallas attorney and prominent Democratic donor who is supporting Biden. “It’s still early.”

The reality is that there is no guarantee either O’Rourke or Castro will make it to Super Tuesday, though the El Pasoan is better positioned at this point in the race.

Other Democrats are staking a flag in Texas, both for campaign contributions and support going forward. Harris, Gillibrand and Warren, among others, have already swung through Texas. Sanders and others did the same on Wednesday, while Buttigieg will join the group in the coming days.

Biden — who, in his announcement on Thursday, stressed the need to get off to a hot fundraising start — will also no doubt make Texas a priority.

"He's got a lot of good friends here," said Stanley, who described the former veep as the "donkey in the room."

Biden isn' t the only heavy hitter, though. Among those donating to Harris is Ron Kirk, the former Dallas mayor who served as Obama’s trade ambassador.

He has a longstanding friendship with the California senator, whom he described as “one of the few candidates who can appeal to the progressive and young folks and not scare away the kind of voters, frankly, we’ve gotta have to win in places like Texas and the middle of the country.”

But Kirk said he wasn’t surprised that other non-Texan Democrats are making inroads.

While “Texas is a state that’s rich in donors, we don’t have a home-town senator” or any other Democratic statewide officials, he said. So a lot of these senators from elsewhere — Harris, Klobuchar, Warren and so on — “have relationships with different donors” in Texas, he said.

“That is our blessing and our curse,” Kirk said.

Those kind of relationships can mean a lot.

Martin, the Gillibrand donor, is the former executive director of Annie’s List, a group devoted to electing progressive women at the state level in Texas. She’s given to a number of the White House contenders over the years, but she’s excited to back the New York senator for 2020.

“She’s highly qualified and very well positioned to win the general election,” Martin said.

Other Texas donors are hedging their bets, with The News review of campaign finance data finding scores of examples of Texans contributing to more than one presidential candidate.

The sample size is too small to draw too many conclusions. But it’s noteworthy that there so far appears to be little overlap between the donor bases of O’Rourke and Castro and that the most common hedges involved contributions to O’Rourke and the likes of Harris and Klobuchar.

Some Texas donors said their multiple contributions simply reflect a quality field, one that features several candidates who do not fit the historic norm of presidents being white men.

Jana Lynne Sanchez — who lost a House race last year against Arlington Rep. Ron Wright — has long admired Klobuchar, so she gave to the Minnesota senator. But she’s also a big O’Rourke supporter and gave to him, as well. And she’s also sent money to Castro and a few others.

“I like so many of the Democratic candidates,” she said. “But most importantly, I just want a candidate who can beat President Trump.”