If you arrived at Beto O'Rourke's recent town hall meeting in San Antonio even 40 minutes ahead of time, you were out of luck. All 650 seats were already taken.

It was one sign that the El Paso Democratic congressman has set Texas Democrats on fire this year, as he takes on Republican Sen. Ted Cruz's re-election bid.

Texas Democrats have been wandering in the electoral wilderness for two decades — 1994 was the last time they won a statewide race — but at O'Rourke's events they have been showing up in droves. Often, it's standing room only.

"Let's make a lot of noise so the folks in the overflow room know we're here, that we care about them," O'Rourke tells the crowd at the town hall, before counting to three and leading them in a cheer of "San Antonio!"

While he was sorry that all of those supporters couldn't see him, Beto O'Rourke is an unapologetic, unabashed liberal, who's shown no interest in moving toward the political middle after his victory in the Texas Democratic primary.

On issues like universal health care, an assault weapons ban, abortion rights and raising the minimum wage, O'Rourke has staked out progressive positions. The Democrat even raised the specter of impeachment after President Trump's Helsinki press conference with Vladimir Putin — although O'Rourke has since walked back that position some.

Nevertheless, recent polls have him just 2 and 6 points behind Cruz. Compare that with the 20-point walloping Texas state Sen Wendy Davis endured in 2014 when she lost in a landslide to Republican Greg Abbott in the race for governor. But that recent history begs the question of whether someone running as far to the left as Cruz can actually win in a state like Texas.

Former Texas agricultural commissioner and Democratic populist Jim Hightower sees something different in O'Rourke's campaign.

"You've got a Democratic constituency that is fed up, not just with Trump, but with the centrist, mealy-mouthed, do-nothing Democratic establishment," Hightower said. "They're looking for some real change and Beto is representing that."

Cruz says he's taking O'Rourke's candidacy very seriously.

"I think the decision he's made is run hard left and find every liberal in the state of Texas, and energize them enough that they show up and vote," Cruz said in an interview with NPR. "And I think he's gambling on there are enough people on the left for whom defeating and destroying Donald Trump is their number-one issue, that he's hoping that his path to victory. I don't see that in the state of Texas. In Texas, there are a whole lot more conservatives than liberals."

When it comes to the critical issue of immigration, the two Texas candidates for Senate couldn't be further apart. Last week in Temple, Cruz indicated he supports ending birthright citizenship telling the crowd, "it doesn't make a lot of sense." O'Rourke is against building a wall along the border and favors a gradual path to legal status for undocumented immigrants.

Political observers in Texas say it's still too early to get a good read on the race, although it seems that O'Rourke's campaign is generating some momentum. Jim Hensen, director of the Texas Politics Project at the University of Texas, which does extensive statewide polling, says the key to O'Rourke's success thus far is that he began his campaign early.

"He's much more viable, he's been working harder, he's traveled all over the state. He started earlier than the statewide candidates that we've seen in recent years, and I think it's made a big difference," Hensen said. Still, Hensen believes an O'Rourke victory is probably a long shot, not for lack of effort or fundraising, but because of the advantage Republican candidates enjoy in Texas when it comes to the sheer numbers of voters.

"In a hundred-yard dash, [O'Rourke] probably starts 10 to 15 yards behind," Hensen said.

At a café in San Antonio where he's come for an interview, O'Rourke can't make it to a table because he's mobbed by customers who recognize him and want a picture together. The congressman patiently chats up everyone who approaches and agrees to pictures. He urges his fans to share the photos on social media, a likely unnecessary piece of advice.

With the recent separations of immigrant children from their parents who are seeking asylum at the Texas border, immigration is hot topic of conversation. "I think that this state, the most diverse state in the country, should lead on immigration," O'Rourke told NPR. "Free DREAMers from the fear of deportation, but make them citizens today so they can contribute to their full potential. That is not a partisan value, that's our Texan identity and we should lead with it."

O'Rourke seems to have no fear of sounding too progressive for Texas. He has no interest in moving toward the ideological center for the general election.

He borrowed an old line from Jim Hightower as way of explanation.

"The only thing that you're going to find in the middle of the road are yellow lines and dead armadillos. You have to tell the people that you want to serve what it is you believe and what you are going to do on their behalf," O'Rourke said. "We can either be governed by fear, fear of immigrants, fear of Muslims, call the press the enemy of the people, tear kids away from their parents at the U.S.-Mexico border, or we can be governed by our ambitions and our aspirations and our desire to make the most out of all of us. And that's America at its best."

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