Republican governor Greg Abbott will face Democrat Beto O’Rourke after voters in Texas opened what could be a lengthy, bruising primary season poised to reshape political power from state capitals to Washington.

Both easily won their party’s nomination for governor on Tuesday.

The GOP primary for state attorney general was more competitive. Donald Trump’s endorsement wasn’t enough to prevent incumbent Ken Paxton from being forced into a May runoff. He’ll face Texas land commissioner George P Bush, the nephew of one president and grandson of another, after neither captured a majority of the votes cast. While Paxton won more votes than Bush on Tuesday, his failure to win outright could raise questions about the power of Trump’s endorsement as he seeks to reshape the party in his image in other primaries later this year.

Abbott is now in a commanding position as he seeks a third term, beginning his run with more than $50m and campaigning on a strongly conservative agenda in America’s largest Republican state.

That leaves O’Rourke facing an uphill effort to recapture the momentum of his 2018 Senate campaign, when he nearly ousted Ted Cruz.

“This group of people, and then some, are going to make me the first Democrat to be governor of the state of Texas since 1994,” O’Rourke told supporters in Fort Worth, where in 2018 he flipped Texas’ largest red county. “This is on us. This is on all of us.”Abbott said, “Republicans sent a message.”

“They want to keep Texas on the extraordinary path of opportunity that we have provided over the past eight years,” his campaign said in a statement.

Democrats faced challenges of their own. Nine-term US representative Henry Cuellar was trying to avoid becoming the first Democratic member of Congress to lose a primary this year. He will instead head into a runoff against progressive Jessica Cisneros.

The primary season, which picks up speed in the summer, determines which candidates from each party advance to the fall campaign. The midterms will ultimately serve as a referendum on the first half of Joe Biden’s administration, which has been dominated by a pandemic that has proven unpredictable, along with rising inflation and a series of foreign policy crises. The GOP, meanwhile, is grappling with its future as many candidates seeking to emerge from primaries, including a sizable number in Texas, tie themselves to Trump and his lie that the 2020 election was stolen.

Tuesday marked the state’s first election under its tighter new voting laws that, among other changes muscled through by the GOP-controlled legislature, require mail ballots to include identification – a mandate that counties blamed for thousands of rejected mail ballots even before election day. More than 10,000 mail ballots around Houston alone were flagged for not complying.

Technical issues also caused problems in Texas’ largest county: paper jams and paper tears in voting machines would take a couple days to work through while counting continues, said Isabel Longoria, Harris county’s elections administrator.

Several voting sites around Houston were also short-staffed, she said, causing tensions in some locations.

Associated Press contributed to this story