AUSTIN, Texas (AP) — Texas' fast-changing politics were put to the test Tuesday as Democratic voters in the giant red state cast ballots in a primary that could wield major influence in choosing who President Donald Trump will face in November.

Democrats have made significant gains recently in the nation's second-largest state and could potentially take control of the state House this year for the first time in two decades.

With a hotly contested presidential race topping the ballot, long lines at polling sites encouraged Democrats who are counting on record-shattering turnout across the state this fall. Vermont Sen. Bernie Sanders, who has given rise to a handful of progressive challengers in Texas, looked to pull away from the field. But a resurgent former Vice President Joe Biden sought to ride a wave of momentum from his huge win Saturday in South Carolina's primary.

It wasn't a smooth start everywhere on Super Tuesday.

Coronavirus fears resulted in a number of poll workers and elections judges not showing up for work Austin, where there have been no confirmed cases. And in San Antonio, technical stumbles caused delays at some polling sites.

In Houston, Rebecca Taylor tried voting in one of the city's historically black neighborhoods where voters waited up to an hour. So she planned to go elsewhere to cast a ballot for Biden after also considering billionaire Mike Bloomberg, who made Houston a centerpiece of his half-billion dollar gambit to win the nomination despite skipping the first four states.

Elizabeth Warren has also vowed to press on and her supporters say she's positioned to nab delegates in Texas.

Taylor said she thought Sanders would scorch other Democrats on the Texas ballot in November if he's the presidential nominee, and she expressed skepticism about whether he could deliver on his promises.

“I just don’t believe he can get in there and do what he says he’s going to do,” she said.

Democrats need only nine seats this fall to flip the Texas House, a goal that is paramount for the party in 2020, particularly because flipping the state outright still faces long odds.

Up and down the ballot, it was a substantial Texas primary that was primed to say a lot about the state's fast-changing politics. Public polling in Texas has shown Biden and Sanders near the top, and

There's also more at stake in Texas than the White House.

Trump threw an endorsement toward rescuing one of the GOP's few women in Congress, Rep. Kay Granger, who is feeling the heat from a conservative firebrand. A newcomer in the Bush dynasty, Pierce Bush, was trying to win a congressional seat in Houston.

For Democrats, a sleepy U.S. Senate race with a dozen candidates hasn't produced a breakout star and appeared headed for a runoff — raising flags for a party that has called Texas a battleground.

The low-wattage race has been far cry from Democrat Beto O'Rourke's barnstorming Senate campaign in 2018. After endorsing Biden Monday night in Dallas, O'Rourke pressed the field to do more.

“I wish that more of them, any of them, would travel to the 254 counties of Texas," O'Rourke told Dallas television station WFAA on Tuesday. “You just cannot pick and choose your voters, and who you'll listen to and who you'll talk to."

Sanders was positioned to seize a significant delegate lead after Texas and 13 other states voted in primary elections Tuesday. Texas is a bonanza with 228 delegates at stake, second only to California, which also was voting Tuesday.

In west Houston, law student Racchel Cabrera, 28, said she voted for Sanders based on his “consistency and lifelong activism for equality" and believes he has the best chance to increase voter turnout for Democrats. She pointed to an increase in Democratic voter turnout during the 2018 midterm election as an example of people wanting to go in a different direction.

“It just shows that people are excited and they’re coming out for progressives,” Cabrera said.

Sanders, a democratic socialist, has raised deep concerns within the party that he is too liberal to beat Trump in November. That angst has particularly spilled into public view in Texas, where Democrats who've been shut out of power for two decades can finally taste a return to relevance.

But Sanders has shown a foothold in Texas, and his success is emboldening a crop of insurgent challengers on the left, challenging the Democratic playbook that suggests ending GOP dominance requires broad-appeal candidates who can attract more voters. Among them are Jessica Cisneros, 26, who Sanders endorsed and is trying to become the youngest member of Congress in a bid against Rep. Henry Cuellar on the Texas border.

“People are looking for leadership right now," said Tory Gavito, president and co-founder of Way to Win, a progressive group founded after Trump’s 2016 win. “With the right top of the ticket, and with the right downballot races, Texas is fair game."

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Associated Press writers Juan A. Lozano in Houston and Jake Bleiberg and Jamie Stengle in Dallas contributed to this report.

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Follow Paul J. Weber on Twitter: https://twitter.com/pauljweber