Tuesday’s primary runoffs in Texas will put President Donald Trump’s endorsement to the test again — the latest step in a mission to punish some incumbent Republicans he has deemed insufficiently loyal.

Trump is backing state Attorney General Ken Paxton in the Senate Republican primary runoff over longtime GOP Sen. John Cornyn, a move that prompted concerns from party members who believe Paxton could put the Senate seat at risk. The winner of the GOP runoff will face state Rep. James Talarico, who won the Democratic Senate nomination in March.

Texas also has a slew of House primary runoffs on tap Tuesday, including one in a battleground district where a secretive group with some Republican links has spent to boost a controversial Democrat. Two Democratic incumbents could also lose House primaries, and a handful of winners in solidly Republican seats will likely be heading to Congress next year.

Polls in most of the state close at 8 p.m. ET and the full state closes at 9 p.m. ET. Here are the major races to watch.

A major Senate race

Trump’s decision to endorse Paxton just one week before the GOP Senate runoff dealt a massive blow to Cornyn, who had also been jockeying for the president’s endorsement. Both the Paxton campaign and Lone Star Liberty, a super PAC supporting him, quickly launched ads touting Trump’s decision.

Paxton and Cornyn are facing off in a head-to-head race for the Republican nomination after neither candidate won a majority of the vote in the March 3 primary. Cornyn finished narrowly ahead of Paxton, 42%-41%, in that contest.

Trump’s endorsement was a late-breaking shift in the race despite months of pressure from GOP leaders, including Senate Majority Leader John Thune, who urged the president to back Cornyn’s bid for a fifth term.

They have argued that Paxton’s controversies could put the Senate seat at risk. The state attorney general was impeached by the Republican-controlled state House on bribery and corruption charges in 2023, though the state Senate acquitted him. Paxton’s wife also announced last year that she was divorcing him on “biblical grounds.”

But Trump ultimately sided with Paxton, describing him as a “True MAGA warrior” and noting Paxton supports eliminating the Senate filibuster to pass Trump’s SAVE America Act, which would overhaul the nation’s voting laws by requiring proof of citizenship to register to vote and a photo ID to cast a ballot.

The president said Cornyn, meanwhile, was “not supportive of me when times were tough,” citing Cornyn’s hesitance to back him in 2016, when the senator stayed neutral in the GOP presidential primary. As Trump was looking to make a comeback in 2024, Cornyn said Trump’s “time has passed him by,” suggesting Trump wasn’t the most electable presidential candidate — though he did eventually endorse Trump.

Cornyn responded to the Paxton endorsement by noting that he supports Trump’s agenda and that Trump “has consistently called me a friend.”

“It is now time for Texas Republican voters to decide if they want a strong nominee to help our GOP candidates down ballot and defeat Talarico in November, or a weak nominee who jeopardizes everything we care about,” Cornyn said.

Cornyn has enjoyed a financial edge in the race, with his campaign and an allied super PAC, Texans for a Conservative Majority, spending nearly $20 million on ads in the race since the March primary, according to AdImpact. The ads have hit Paxton on his record in state office and past controversies. Paxton and an aligned outside group, Lone Star Liberty PAC, have spent around $5 million, largely slamming Cornyn on immigration.

A controversial contested seat

The Democratic primary runoff in Texas’ 35th Congressional District has captured national attention, as a shadowy outside group with some GOP links has boosted a long-shot Democrat condemned by party leaders as antisemitic.

Most Democratic elected officials have backed Johnny Garcia, who works in the Bexar County Sheriff’s Office. But the runoff also includes sex therapist Maureen Galindo, who finished the first round narrowly ahead of Garcia despite having raised virtually no money.

Galindo has faced broad criticism for a litany of controversial comments. Most recently, Democratic House leaders condemned her last week over an Instagram post in which she said she’d turn an Immigration and Customs Enforcement detention center “into a prison for American Zionists and former ICE officers for human trafficking” and that many Zionists are “pedophiles.”

Meanwhile, a super PAC that has yet to disclose its donors, Lead Left PAC, has spent about $1 million to boost Galindo. But while the group has no real footprint, Punchbowl News reported it was previously linked to a GOP fundraising platform, leading to speculation that Republicans are boosting her in order to make the district noncompetitive in the general election.

Texas is no stranger to having a surprise runoff featuring a gadfly — but the stakes are higher for this one because Democrats are hoping to put this district on the battleground map if Garcia wins his primary, even though it is one of the seats state Republican leaders redrew last year. Trump carried this slice of territory stretching from Austin to San Antonio by 10.5 points in 2024.

Republicans have an interesting runoff of their own, with Trump and Gov. Greg Abbott in a rare proxy battle. Air Force veteran Carlos De La Cruz — the Trump-backed brother of Rep. Monica De La Cruz — faces state Rep. John Lujan, who is backed by Abbott and was the leading vote-getter in March, for the GOP nomination.

Which incumbent House members will fall?

At least one Democratic member of Congress is guaranteed to lose Tuesday, since Reps. Christian Menefee and Al Green are facing off after the Republican redistricting effort put them in competition for a single redrawn Houston seat. The race has exposed the Democratic Party’s generational divide: Menefee, who joined Congress just a few months ago after winning a special election, is 37 years old, while Green is 78.

Menefee has argued he’d be a more effective legislator, and he has benefited from more than $2 million in outside spending from a super PAC tied to the crypto industry, while Green has pointed to his long record serving the area in Congress, and his vocal opposition to Trump, to try to save his career.

Meanwhile, in the Dallas metroplex, Rep. Julie Johnson and former Rep. Colin Allred are running in another contested Democratic runoff. Allred, a former professional football player who ran for Senate in 2024, finished with more votes than Johnson in the first round, 44% to 33%, but both have been campaigning hard in a district that was significantly redrawn.

Allred is framing himself as a fighter against Trump and has been deeply critical of redistricting efforts he says amount to attempts to dilute Black voting power. Johnson has leaned on her legislative record and has criticized Allred for past votes on immigration.

Who else punches a ticket to Congress?

A handful of runoffs in other safe Republican seats will likely decide who joins Congress next year.

The Houston suburbs feature another runoff between candidates backed by Trump and Abbott. Military veteran Alex Mealer finished narrowly ahead of state Rep. Briscoe Cain in the first round of voting in the 9th District. Mealer has Trump’s backing and support from multiple outside groups, and she and her allies have vastly outspent Cain on the airwaves in the runoff. Cain, Abbott’s pick, has pointed to his conservative chops and legislative record as he looks to score an upset.

In the nearby 38th District, Trump-backed Jon Bonck, who works in real estate, fell just short of a majority during the first round and is facing Shelly deZevallos, a conservative activist and pilot who’s served on both federal and state government advisory committees. Trump and congressional leadership are backing Bonck, but deZevallos has endorsements from a handful of members of Congress, too.

And in West Texas, former congressional aide Tom Sell fell just short of winning the 19th District’s primary to succeed retiring Rep. Jodey Arrington. Now, he’s in a runoff with Abbott-backed conservative activist Abraham Enriquez. Outside spending from a pro-AI super PAC funded primarily by Andreessen Horowitz and OpenAI has boosted Sell’s campaign.

Who will succeed Paxton as attorney general?

Trump hasn’t picked a side in the competitive GOP runoff in the attorney general’s race, but he’s still been an important factor in the race between state Sen. Mayes Middleton and Rep. Chip Roy.

Middleton, a wealthy oilman and former head of the state House’s Freedom Caucus, has sunk millions of his own money into his bid. He calls himself “MAGA Mayes,” pointing to his conservative record in the Legislature and criticizing Rep. Chip Roy over his past breaks with Trump. Middleton has accused Roy of supporting Trump’s impeachment even though Roy voted against it, though the congressman said at the time that Trump “deserves universal condemnation for what was clearly impeachable conduct” around the Jan. 6, 2021, Capitol riot.

Roy, a member of the U.S. House’s Freedom Caucus and a former chief of staff to Sen. Ted Cruz, has carved out a lane as a libertarian-tinged lawmaker who has been a thorn in the House GOP’s side at times. Roy has leaned on support from Cruz and has been a big proponent for Trump’s SAVE America Act. But Roy was an early backer of Florida Gov. Ron DeSantis’ 2024 presidential campaign, and he initially raised concerns about Trump’s “big, beautiful bill” last year before ultimately voting for it.

There’s also a Democratic runoff here, too, between former Galveston Mayor Joe Jaworski and state Sen. Nathan Johnson. But a Democrat has not won a statewide race in Texas since 1994.