Rep. Beto O'Rourke Beto O'RourkeJimmy Carter says his son smoked pot with Willie Nelson on White House roof O'Rourke endorses Kennedy for Senate: 'A champion for the values we're most proud of' 2020 Democrats do convention Zoom call MORE (D-Texas) is facing a pivotal moment in his upstart fight to defeat GOP Sen. Ted Cruz Rafael (Ted) Edward CruzCruz blocks amended resolution honoring Ginsburg over language about her dying wish Trump argues full Supreme Court needed to settle potential election disputes Press: Notorious RBG vs Notorious GOP MORE.

O'Rourke shattered fundraising records with a stunning $38.1 million haul between July and September — the largest quarterly haul in U.S. Senate history and more than tripling Cruz’s $12 million.

It was a sensational fundraising number that has exceeded some presidential hauls, and reflects how O'Rourke has taken the political world by storm with his bid to upset Cruz, a former presidential candidate and conservative firebrand with his own national following.

Yet, O’Rourke’s fundraising prowess distracts from the reality that Cruz is ahead in the race, and appeared to have strengthened his position during the contentious and deeply partisan fight over Justice Brett Kavanaugh Brett Michael KavanaughHarris faces pivotal moment with Supreme Court battle Poll: 59 percent think president elected in November should name next Supreme Court justice Feinstein 'surprised and taken aback' by suggestion she's not up for Supreme Court fight MORE's Supreme Court confirmation.

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O'Rourke's challenge is to keep up his momentum, something that he'll seek to do at a critical debate on Tuesday night, their second of the race.

“I think this money represents a tremendous bump for Beto. The need to get the campaign from registration mode to mobilization mode is imperative,” said Brandon Rottinghaus, a political science professor at the University of Houston.

Political observers say Democrats’ biggest problem in Texas elections is turnout, particularly in historically low-turnout midterm cycles.

They argue O’Rourke needs to mobilize Democrats, while also swaying independents and swing voters dissatisfied with President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE — a costly and time-intensive feat to execute in the final three and a half weeks of the campaign.

“This gives them enough ammunition to prosecute an air war and ground war, both of which they desperately need to overcome the natural, organic advantages Republicans have in midterm years,” Rottinghaus said.

O’Rourke, who’s represented his El Paso-based district since 2013, has gotten a groundswell of national attention over the past year, which has resulted in a boom of small-dollar donations from around the country.

ActBlue, the online fundraising platform used by Democrats, has helped him raise tens of millions of dollars.

Plus, he’s made social media a key part of his strategy to engage new and young voters.

He filmed a TV ad through Facebook Live when the previously scheduled second Senate debate was canceled.

And he has benefited after moments from his campaign have gone viral, including his comments about why he supports NFL players who kneel during the national anthem.

Still, while his high-dollar fundraising gives him an opportunity to compete in the expansive deep-red state, Texas strategists wonder how far that money can go at this point in the race.

They pointed out that most of the TV airtime has been booked by Cruz, super PACs supporting him and Texas Gov. Greg Abbott (R), who’s running for reelection.

“There’s only so much money you can put into social media to connect to voters you need to vote to win,” Rottinghaus said.

“The people they want to target are either nonvoters which are hard to reach, and swing voters who may support Republicans who are unhappy with Trump or Cruz.”

Republicans acknowledge O’Rourke’s prolific fundraising abilities, but they believe it still won’t help him overcome Cruz’s consistent polling lead and the traditionally red dynamics of Texas.

Though polls had shown a tight race through the summer, Cruz has regained his footing, with a recent Quinnipiac University poll showing him up by 9 points and a New York Times/Siena College survey having him ahead by 8 points. And both polls show that only a small amount of voters are undecided.

O’Rourke has never led a public poll.

Democrats haven’t won statewide office in the Lone Star State since 1994, nor a U.S. Senate seat since 1988.

“That's a lot of money. But I think all the money in the world is not going to help Beto at this point because I think he is self-identified as a national Democrat which means he's way too liberal to get elected in Texas,” Senate Majority Whip John Cornyn John CornynThe Hill's Campaign Report: GOP set to ask SCOTUS to limit mail-in voting Liberal super PAC launches ads targeting vulnerable GOP senators over SCOTUS fight Senate GOP faces pivotal moment on pick for Supreme Court MORE (R-Texas) told reporters at the Capitol on Friday.

"It's the adoring coverage in the media and he's obviously captured a lot of people’s imagination and the ability to raise money through these portals like ActBlue, small donations,” he added. “Good for him, but I still don't think he's going to win."

One factor that has helped solidify that lead is Kavanaugh’s confirmation to the high court.

Kavanaugh's nomination was almost derailed by allegations that he sexually assaulted California professor Christine Blasey Ford when they were both in high school, which he has strongly denied.

Kavanaugh’s confirmation galvanized the GOP base, which has helped the party make up the enthusiasm gap that Democrats have been enjoying throughout most of the election cycle.

“I think the race has moved sharply in Cruz’s direction in the last month. Republicans have really come home, part of that is Kavanaugh and the race appearing to be close and the value of the Senate seat,” said Matt Mackowiak, GOP strategist based in Texas.

The debate in San Antonio on Tuesday now gives O'Rourke a chance to go on offense in what’s likely to be the final debate of the campaign.

O’Rourke went toe-to-toe with Cruz, who was a champion debater at Princeton University, at last month's debate, but the GOP senator aggressively went after his opponent and largely kept him on defense as they sparred over hot-button issues like immigration, police shootings and NFL anthem protests.

The focus on culture war issues has generated sky-high enthusiasm among their bases in an already deeply polarized electorate, but political strategists warn it will be a tricky balancing act for Beto, who can't afford to lose his base of liberal voters but also needs to sway enough independents to vote for a Democrat in the conservative state.

“In this debate, O’Rourke can only go in with one serious tactic: to keep the base mobilized,” said Rottinghaus, the political science professor.

“Kavanaugh clearly generated enthusiasm. O’Rourke can make that happen by the counterenthusiasm from Democrats.”

But Mackowiak, the GOP strategist, said that a strategy focused largely on energizing the base will make it difficult for O’Rourke to find a path to victory in a statewide campaign.

“Firing up liberals is a good way to lose a Senate race in Texas by 10 to 15 points if that’s the entirety of your strategy,” he said, adding that he hasn’t seen O’Rourke move to the center on many issues.

— Jordain Carney contributed.