Democrats have already dealt a scare to Republican incumbents with a heavy dose of prodigious fundraising ahead of the fall campaign. But three long shots in particular have burst onto the scene as financial juggernauts.

In Texas, Rep. Beto O’Rourke (D) has hooked his fundraising engine onto the liberal loathing of Sen. Ted Cruz (R). In Wisconsin, Randy Bryce, an iron worker, has tapped into the left’s venom for House Speaker Paul D. Ryan (R). And in California, Andrew Janz went from being an obscure local prosecutor to liberal hero challenging Rep. Devin Nunes (R), chairman of the House Intelligence Committee.

All three Democrats began their campaigns last year among the longest of long shots to knock off these well-entrenched Republicans — yet donors don’t really care. Liberal activists want Democratic majorities on Capitol Hill, but they also want trophy seats, to defeat major symbols of the GOP movement in the age of President Trump.

O’Rourke’s $6.7 million haul over the last three months is likely to be the most raised by any candidate. It is the most money ever raised in a Texas Senate race from donors in a single quarter, according to the Federal Election Commission.

Nationally, only nine Senate candidates have ever raised more from contributions in a quarter than O’Rourke just did, and most of those candidates were major figures, such as Hillary Clinton in her 2000 campaign and Sen. John McCain (R-Ariz.) after he was his party’s presidential nominee. (A few other super-rich candidates spent more money, but only by funding the campaigns themselves.)

O’Rourke credits his fundraising surge to the ethos of his campaign — forbidding any PAC donations, liberal or conservative — which he says energizes individual donors to believe they have more control over the campaign.

“People are responding in numbers well beyond anything we could have expected,” O’Rourke said in a telephone interview Friday.

Bryce’s $2.1 million is $600,000 more than what Ryan raised in the last quarter of 2017. And Janz’s reported $1 million haul for the first quarter of 2018 almost matches what Nunes raised for all of last year.

This is part of a broader trend in which Democrats are swamping Republicans so far this election season. A Politico analysis found that, in the last quarter of 2017, more than 40 House Republicans raised less money than one of their Democratic challengers.

Overall for 2017, according to the FEC, all Democratic candidates for the House raised $63 million more than their GOP counterparts, a reversal from the 2016 campaign, when Republicans raised nearly $85 million more.

Senate Democrats are also raising money at record clips. Sen. Robert P. Casey Jr. (D-Pa.) announced Friday that he had more than $10 million cash on hand, the most any Pennsylvania Senate candidate has held at this stage of a campaign.

But money is not enough for longer-shot candidates such as O’Rourke, Bryce and Janz.

Rick Lazio learned this lesson in 2000. Then a Republican congressman from Long Island, he jumped into the race against Clinton (D-N.Y.) after Rudolph W. Giuliani bowed out in May 2000. In just six months, Lazio brought in nearly $40 million, riding a national fundraising machine built upon conservative hatred of Clinton.

Clinton thumped Lazio by more than 12 percentage points, effectively ending his career.

The lesson? When running against an opponent who is reviled by the other side, a smart campaign can raise enormous amounts of money. But money usually cannot overcome a candidate who is out of step ideologically with the state’s voters.

O’Rourke’s fundraising and work ethic are unquestioned. O’Rourke spoke to The Washington Post during a 1,600-mile week-long drive across Texas that began Tuesday in Waco and ends Monday in Lubbock.

He recently held a rally in Roanoke, a northwest suburb of Dallas in a heavily Republican County. A thousand people showed up. “Something is happening right now,” he said.

However, in last month’s primaries, Cruz received twice as many votes as O’Rourke received in the Democratic primary.

Those results proved that, despite a boost in Democratic turnout in the primary, O’Rourke needs more than a “blue wave” to defeat Cruz.

“There just aren’t enough Democratic votes. If he is going to make any progress, he’s going to need a lion’s share of the independent vote, and he has to cut into the GOP base. That’s pretty tough,” said Jennifer Duffy, the Senate analyst for the Cook Political Report.

In Ryan’s southern Wisconsin district, Bryce faces a similarly difficult terrain. Ryan, a 20-year incumbent, has received less than 60 percent of the vote in just one of his reelection bids. Moreover, in the past four partisan elections, no Democrat running statewide has ever won a majority in Wisconsin’s 1st Congressional District, according to Nathan Gonzales, the editor of Inside Elections.

So far, there has been little reliable polling to gauge Bryce’s standing. “I prefer to wait for credible polling data on this race specifically. I know he has raised a ton of money, but I’m not convinced he’s running a great campaign,” Gonzales said.

Democrats do not consider these campaigns a problem — they’re happy to have these candidates running and even happier that they are raising so much money. If the races get close in the fall, these candidates will not require much help from Democratic super PACs and other Democratic outside groups.

Plus, if O’Rourke pulls off the upset, it would open a path for the Democrats to win a Senate majority, which was almost unthinkable a year ago.

In the House, no Democratic strategist ever drew up a path to winning the majority by defeating Nunes — in eight campaigns, he has never faced a competitive race against a Democrat. Several dozen Republicans hold seats where Trump fared worse.

But liberals turned their attention toward Nunes as his profile skyrocketed, particularly after his committee released a controversial report questioning the underpinnings of special counsel Robert S. Mueller III’s investigation of Russia’s efforts to interfere in the 2016 campaign.

Nunes went from a low-profile chairman to a conservative boogeyman that the left needed to defeat. Janz, 34, running his first campaign, went from being a local prosecutor to a million-dollar man on the campaign trail.

“The national attention is good,” Janz told NBC News in late February, “because, you know, we’re going to need to raise the resources to be able to tell my story.”