KATY — The photo line for Beto O’Rourke here Saturday afternoon quickly turned into something of a reunion.

“Hey, I know who you are!" a characteristically sweat-drenched O'Rourke told one supporter. After talking to another, O'Rourke yelled out to an aide: "Hey, someone who worked on the campaign wants to be plugged in again!"

The vibe was similar a day later in Plano, where O'Rourke rallied in front of signs reading, "Welcome to Beto Country," serving up nostalgia from his near-miss loss to U.S. Sen. Ted Cruz last year. He said the Senate race was the "only reason" he got to run for president, touting the support he built in Collin, Denton, Tarrant and Dallas counties before getting drowned out by cheers.

"Hold on, I've got 250 other counties I want to mention," he added cheekily, a nod to his all-county tour in that race.

O’Rourke will need the voters in these places, particularly Katy and Plano, if he wants to make good on a central tenet of his White House pitch — that he is uniquely positioned to not only win the Texas primary, but also to deliver the state for Democrats in the general election for the first time in over four decades. While he's polling low elsewhere, O'Rourke has remained near the top of primary polls in Texas, along with national frontrunner Joe Biden, though he has encountered new headwinds with two recent surveys showing Elizabeth Warren overtaking him for second place.

O'Rourke's weekend swing through the Houston and Dallas suburbs took him to historically Republican counties that he dramatically swung last year — places that illustrate the upper hand he believes he has even as his statewide standing slips.

"As was just reinforced today, no one has the network like the network that we helped to build in 2018, and that still exists in 2019 going into 2020," O'Rourke told reporters after the Katy event. "So I believe that as we engage this network ... in places like Fort Bend, but also in places like Amarillo or Longview, we're going to be able to produce the majority that wins the delegates and also, importantly against Donald Trump, wins the [state's] 38 electoral votes."

O’Rourke’s more immediate reason for being in Katy — part of which is in Fort Bend County — was to campaign for Eliz Markowitz, the sole Democratic candidate in a November special election for a state House seat that the party is aiming to flip. A win would give Texas Democrats a burst of momentum as they work to capture the House majority next year, and O’Rourke is easily the highest-profile Democrat to get involved in the race yet.

O’Rourke went door-knocking Saturday with Markowitz, a 2018 nominee for the State Board of Education, and then held a rally with her outside a Katy brewery.

“The road to 2020 runs through 2019, the road to America runs through Texas, and the road to Texas runs through Fort Bend County,” O’Rourke said at the rally. “So we cannot be in a more important place at a more important time than where we are at this moment.”

While Biden and Warren are posing threats to O’Rourke’s statewide support, there are so far few signs that his rivals are contesting him in the kind of places that he visited this weekend. Fellow Texan Julián Castro drew a big crowd in Collin County after his memorable performance — at O'Rourke's expense — in the first debate earlier this summer, but the Democratic presidential candidates otherwise have not strayed outside the state's major urban centers.

"It's a good idea for him to continue to come to places like this — I think the people are there," O'Rourke backer Jennifer Seibert of Allen said as she waited for a photo Sunday in Collin County.

O’Rourke drew large crowds in Katy and Plano, and long, winding photo lines formed for him afterward amid near-triple-digit temperatures. Speaking after O’Rourke in Katy, the chairwoman of the Fort Bend County Democratic Party, Cynthia Ginyard, touted the connection that O’Rourke made with the county “long before everyone knew him,” recalling a campaign stop he made there in 2017 that drew a larger-than-expected crowd.

“We took him over in the 2018 election and Fort Bend, we were there for him,” she said, “and we are going to be there for you, Beto, in the future.”

O’Rourke has evolved as a politician since the last time he asked for votes of Texans in the traditionally Republican suburbs. Most recently – and most notably — O’Rourke came out in support of a mandatory buyback program for assault weapons after the deadly shooting last month in his El Paso hometown.

It was a position that he touted to much fanfare at the latest primary debate Thursday in Houston, where he vowed “hell, yes,” he wants to take away people's AR-15s and AK-47s.

O’Rourke did not shy away from the proposal in less Democratic territory this weekend, drawing arguably his biggest applause line in Plano as he said, “We are going to buy back every single one of those weapons, take them off the streets and ensure they are never used against us.” The declaration drew sustained cheers that gave way to chants of “Hell, yes!”

His aggressive anti-gun violence agenda is a stark shift from the Senate race, when he supported an assault weapons ban but swore to Texans he did not want to take away their guns. He acknowledged that El Paso "changed a lot," but disputed the disputed the notion that he could turn off the kind of independent and Republican-leaning Texans who went for him last year.

"In fact, I think that independent voters and Republicans care just as much about their kids as any Democrat does, and they want to do the right thing, and this campaign’s gonna give them a way to do the right thing," O'Rourke said.

Before O'Rourke spoke in Katy, Markowitz gave a fiery speech railing against Republicans who "care more about weapons of war than our children." Afterward, she told The Texas Tribune she supports gun-related proposals, including universal background checks and red-flag laws, but "would be hard-pressed to say that I would do a mandatory buyback at this point in time."

Still, Markowitz said Democrats are far more united on guns than divided as she drew broad comparisons between her campaign and O'Rourke's.

"I think that a lot of the reasons that people rallied around Beto are a lot of the same reasons they're rallying around our campaign," she said. "I think people, especially in Fort Bend County and District 28, are tired. They're tired of the divisiveness and they're ready for change, and we're going to bring that change to Fort Bend County in 52 days."

Another way O’Rourke has changed, at least in the eyes of his onetime skeptics within the Democratic Party: a willingness to be more of a team player.While he appeared with and promoted down-ballot candidates during the 2018 cycle, some thought he could have done more to share the massive spotlight he earned and especially would have liked him to be more involved in the race to unseat his friend, U.S. Rep. Will Hurd, R-Helotes.

Not only did O’Rourke stump Saturday with Markowitz, but another state House candidate, Jenna Royal, introduced him in Plano, and he spent some of his opening remarks praising her selflessness as an organizer for his 2018 campaign. And he further pitched in on House races Saturday evening when he sent a fundraising email for Josh Markle, the Democrat challenging state Rep. Briscoe Cain, R-Deer Park, who landed in national headlines Thursday night for tweeting at O'Rourke, "My AR is ready for you."

It does not hurt that these candidates provide alliances in suburban areas that could be key to 2020 success in the state — and to keeping his loyalists engaged after last year. They include people like Dylan Russell, a 45-year-old Missouri City attorney who never volunteered for a candidate until O'Rourke's 2018 campaign and is now door-knocking for his presidential bid in Fort Bend County.

"A lot of people are excited about his campaign," Russell said after the Katy event, wearing an O'Rourke campaign T-shirt bearing his visceral reaction to the El Paso massacre — "This is f*cked up" — with a Markowitz sticker on it. "Obviously, we have a lot more choices than we did in 2018, so I talk to people who are supporters of other campaigns right now, but I don't think anybody dislikes Beto. Most people like Beto. They just have different preferences as far as the president right now."