Here's what to watch for in the Texas primary runoff election today

The most expensive Senate primary in history finally came to a close on Tuesday when Texas Republicans chose Attorney General Ken Paxton in a GOP runoff, ousting incumbent Sen. John Cornyn.

Several other races from the March 3 primary are also on the runoff ballot Tuesday, including attorney general, state railroad commissioner and a number of congressional races.

Polls closed at 7 p.m. Central Time across most of Texas, and will close an hour later in the state's westernmost corner.

Here are some of the major races to watch:

Cornyn and Paxton faced off in the primary runoff after neither received a majority in the March primary. The race could have a seismic impact on the Senate — especially after President Trump last week threw his endorsement behind Paxton.

Paxton defeated Cornyn in the runoff, CBS News has projected.

Cornyn, first elected in 2002, came out as the top vote-getter in the three-way primary in March but failed to secure at least 50% of the vote. The former Republican whip and chair of the Senate GOP fundraising arm, Cornyn had sometimes been at odds with Mr. Trump, although he has been an ally to the president in his second term. Paxton, meanwhile, had been a staunch supporter of Mr. Trump for years.

No Democrat has won statewide office in Texas since 1994, making Paxton the favorite to win in November.

Mr. Trump's lack of endorsement had been a defining feature of the race, with reports floating after the primary that he would back Cornyn. Two days after the primary, Mr. Trump said he would endorse "SOON" and called on whoever he chose not to endorse to drop out. Paxton, meanwhile, said he would only drop out after the Senate passed a voter ID law backed by Mr. Trump known as the SAVE America Act.

Mr. Trump held a rally in Texas in March, but did not throw his support behind any candidates at that time, allowing the deadline to be removed from the ballot to pass without making his endorsement. One day after early voting for the runoff started, and six days before voting day, he backed Paxton.

"The moment Donald Trump endorsed Ken Paxton, he took a somewhat unlevel playing field and turned it into a steep cliff," said Rice University political science professor Mark Jones.

Mr. Trump's endorsements have carried weight in Republican contests earlier this month. In Louisiana, he endorsed Sen. Bill Cassidy's opponent, and the incumbent then failed to advance to the runoff. In Kentucky, frequent Trump antagonist Rep. Thomas Massie was defeated by a challenger backed by the president.

Republicans had generally viewed Cornyn as a stronger candidate against James Talarico, who won the March Democratic primary. The Senate Republican fundraising arm invested millions to defeat Paxton, and Paxton overall had a weaker fundraising record than Cornyn — meaning Senate Republicans will have to spend more money supporting Paxton in the general election race, after already spending millions opposing him.

Asked last week whether the president's endorsement of Paxton would make it more difficult for Republicans to hold onto control of the Senate, Majority Leader John Thune replied that "the majority runs through a lot of different states."

Paxton was first elected Texas attorney general in 2014, aggressively taking on the Obama administration when he assumed office. He then became a close ally of Mr. Trump's, going so far as to file the lawsuit challenging former President Joe Biden's win in the 2020 election in Pennsylvania, Michigan, Georgia and Wisconsin. That case was tossed out by the U.S. Supreme Court.

Paxton also has a history of legal issues related to his role as attorney general.

In 2015, he was indicted on securities fraud charges, but they were later dropped in 2024 as part of a pre-trial diversion deal. In 2023, he was impeached on charges of bribery, dereliction of duty and disregard of official duties by the GOP-majority Texas House of Representatives in a 121-23 vote. He was later acquitted by the state Senate. Mr. Trump posted a message in support of Paxton after the trial.

The contest between Cornyn and Paxton was the most expensive primary on record, with AdImpact reporting that spending across both the March primary and Tuesday runoff topped over $120 million in advertising alone.

After Texas' Republican-controlled Legislature redrew congressional districts to create five additional seats that are more favorable to the GOP, the Democratic primary runoff in the state's 18th Congressional District pitted two incumbents against each other.

Rep. Christian Menefee defeated Rep. Al Green in a runoff on Tuesday, CBS News projected.

Menefee and Green advanced to a runoff in March after neither secured more than 50% of the vote in the primary. Menefee was the top vote-getter in March, and a University of Houston poll from earlier this month showed Menefee winning over supporters of another candidate, Amanda Edwards, from the March race.

Green, 78, who has represented the 9th Congressional District since 2005 and is known as a Trump antagonist, opted to run in the 18th District after Republicans scrambled the boundaries of his district to make it more Republican-leaning.

Menefee, 38, won a special election earlier this year to replace Democratic Rep. Sylvester Turner, who died in March of last year.

The district is heavily Democratic, so the winner of Tuesday's primary will be favored to win in November.

Democrats are trying to stop Maureen Galindo, who is accused of antisemitism, from winning the Democratic primary runoff in Texas' 35th Congressional District.

Galindo, a sex therapist, is up against Johnny Garcia, a former sheriff's deputy, in the San Antonio-area district that has shifted redder after Texas Republicans redrew the congressional map.

Galindo led the March primary, earning 29% of the vote compared with Garcia's 27%.

After she called for the imprisonment of "American Zionists," House Democrats condemned Galindo, with some saying they would force a vote to expel her if she prevails in the runoff and general election.

"If for some crazy reason she gets elected … I will vote and make a motion to expel her every single day that we're here," Democratic Rep. Josh Gottheimer of New Jersey, who is Jewish, said last week.

The Democratic Congressional Campaign Committee got involved in the race last week, placing a last-minute ad buy as the House Democrats' campaign arm sought to tip the scales in Garcia's favor. The ad referred to Galindo as "MAGA Maureen," in reference to support she's received from a political action committee that has been linked to Republicans.

Talarico, Texas Democrats' Senate nominee, has endorsed Garcia over Galindo and said he won't campaign with Galindo if she becomes the nominee. Incumbent Rep. Greg Casar, who currently represents 10% of the district since it was redrawn and is instead running in the 37th District in Austin, has backed Garcia.

There is also a runoff for Republicans in the district, which now covers parts of San Antonio and some suburbs. State Rep. John Lujan is facing off against Carlos De La Cruz, the brother of Rep. Monica De La Cruz of the 15th District.

Democratic incumbent Rep. Julie Johnson is facing former Rep. Colin Allred in the newly-redrawn Dallas-area 33rd District, the final act in what has shaped up to be a nasty primary matchup.

Johnson was first elected in 2024, when Allred, who had flipped the former 32nd District in 2018, opted to instead run for Senate against Ted Cruz. Allred ultimately lost, but finished five points ahead of Vice President Kamala Harris statewide in that cycle.

But Johnson's current district, which includes parts of Dallas and its suburbs, had been altered during Texas Republicans' 2025 redistricting push, turning it from a district that was 62% Democratic in 2024 to one that's projected to be 41%. Longtime Rep. Marc Veasey's 33rd District, which now only includes Dallas County, remained strongly Democratic, but he decided not to run for reelection, and Johnson is now vying to replace him.

Allred, meanwhile, had initially jumped into the U.S. Senate race again. He dropped out after Rep. Jasmine Crockett, who had represented another Dallas-area district that was redrawn, decided to run in that race. Allred then got his paperwork in on the filing deadline to run against Johnson and two others in the 33rd Congressional District.

Allred received the most votes in March, coming out more than 10 points ahead of Johnson but failing to secure the 50% of the vote needed to avoid a runoff. Since then, Allred and Johnson have blasted each other's records in Congress. Allred has enlisted Crockett on the campaign trail, while Talarico is backing Johnson.

The district is heavily Democratic. There is runoff between Republican candidates Patrick David Gillespie and retired police officer John Sims in the district, but neither would be expected to win the general election.

With Paxton running for Senate, conservatives statewide are split in the runoff for attorney general. Even before the race headed into the runoff, it was already the most expensive attorney general race in the country's history.

U.S. Rep. Chip Roy finished second in the March primary to state Sen. Mayes Middleton. Although Mr. Trump has not weighed in, Middleton has attempted to depict Roy as not being loyal enough to the president and his agenda. Roy was one of a handful of Texas Republicans to vote against Cruz's attempt to object to the 2020 election results in Arizona and Pennsylvania, and he delivered a speech after the Jan. 6, 2021, attack on the U.S. Capitol criticizing Mr. Trump. But he voted against impeaching him one week later.

Roy served as Paxton's first assistant attorney general before being elected to Congress and has criticized Middleton for working as an executive in the oil and gas industry. Middleton has said he is a practicing attorney in oil and gas law.

A statewide poll from the University of Houston earlier this month had Middleton leading 48% to 39%, although 13% remained undecided. Lt. Gov. Dan Patrick, the second-highest statewide official, is backing Middleton, while Roy is backed by Cruz.

Democrats are also in a runoff for their nomination, with state Sen. Nathan Johnson facing off against former Galveston Mayor Joe Jaworski.

Texas' railroad commissioners regulate the state's oil and gas industry, making the three-person commission one of the most powerful agencies in the state — and one that attracts a lot of money. The commissioners are elected to staggered six-year terms.

Chairman Jim Wright is being challenged by Bo French, the former Tarrant County GOP chair. Republican leaders had asked French to step down last year after he posted a poll on social media asking whether Jews or Muslims are "a bigger threat to America." French, whose family owns an oil company in Midland, resisted those calls and only stepped down this year to focus on running for railroad commissioner. He has focused part of his campaign on what he called the "Islamic invasion of Texas," while also calling for the U.S. to deport 100 million people, including Native Americans.

In the March primary, Wright received 32.1% of the vote and French received 31.75%, according to The Associated Press.

Wright has been backed by the other two railroad commissioners, as well as Gov. Greg Abbott, Patrick, a slew of other elected Republicans and the Texas Oil and Gas Association Good Government Committee. French has received the backing of Turning Point Action and two GOP congressional nominees — state Rep. Steve Toth, who defeated Rep. Dan Crenshaw in the March primary, and Brandon Herrera, the nominee in the 23rd District.

"You know Bo French has crossed the line on the ideological spectrum when Gov. Abbott and Lt. Gov. Patrick consider him to be an extremist," Jones, the political science professor, said.

Jones said French generally does better with Paxton voters than Cornyn voters — meaning if Cornyn voters don't show up on Tuesday, there's a chance French wins the nomination.