<div class="css-s99gbd StoryBodyCompanionColumn" data-testid="companionColumn-0"><div class="css-53u6y8"><p class="css-ac37hb evys1bk0">Senator John Cornyn, a longtime fixture of Republican politics in Texas, is facing a fierce runoff challenge from a Trump-backed rival who could bring his decades-long career in government to an end.</p><p class="css-ac37hb evys1bk0">Here are five things to know about Mr. Cornyn, 74, of Austin, Texas, who <a class="css-yywogo" href="https://www.nytimes.com/interactive/2026/us/elections/results-texas-primary.html" title="">narrowly led</a> in the first round of primary voting in March.</p><p class="css-ac37hb evys1bk0"><strong class="css-8qgvsz ebyp5n10">1. He has occasionally criticized President Trump. </strong>Mr. Cornyn <a class="css-yywogo" href="https://www.nytimes.com/interactive/2021/01/07/us/elections/electoral-college-biden-objectors.html" title="">accepted Joseph R. Biden Jr.’s victory</a> in the 2020 election, and he said in 2023 that Mr. Trump’s time had “<a class="css-yywogo" href="https://www.nytimes.com/2025/05/30/us/cornyn-paxton-texas-primary.html" title="">passed him by</a>.” Last year, Mr. Cornyn said, “I was wrong, and President Trump was right, obviously.”</p><p class="css-ac37hb evys1bk0">Mr. Trump stayed neutral in the initial round of voting and for much of the runoff, which pits Mr. Cornyn against Texas’ <a class="css-yywogo" href="https://www.nytimes.com/2026/03/03/us/politics/ken-paxton-republican-senate-candidate.html" title="">hard-right attorney general, Ken Paxton</a>. But Mr. Trump, who has been on a run of wins in his campaign to oust his <a class="css-yywogo" href="https://www.nytimes.com/2026/05/19/us/politics/trump-massie-primary-takeaways.html" title="">Republican critics in primaries</a>, endorsed Mr. Paxton last week. In a statement, <a class="css-yywogo" href="https://truthsocial.com/@realDonaldTrump/posts/116602192066577324" rel="noopener noreferrer" target="_blank" title="">the president hailed</a> Mr. Paxton’s “loyalty.” Mr. Cornyn <a class="css-yywogo" href="https://x.com/JohnCornyn/status/2056781893681467545" rel="noopener noreferrer" target="_blank" title="">responded on social media</a> that it was “time for Texas Republican voters to decide if they want a strong nominee,” adding, “I trust the Republican voters of Texas.”</p></div><aside aria-label="companion column" class="css-ew4tgv"></aside></div><div data-testid="Dropzone-1"></div><div class="css-s99gbd StoryBodyCompanionColumn" data-testid="companionColumn-1"><div class="css-53u6y8"><p class="css-ac37hb evys1bk0"><strong class="css-8qgvsz ebyp5n10">2. He has served in party leadership. </strong>From 2013 to 2019, Mr. Cornyn was the No. 2 Republican in the Senate. He served as the party whip, responsible for counting and securing votes. Before that, he was chair of the National Republican Senatorial Committee, the campaign arm of Senate Republicans. (The committee has backed Mr. Cornyn in this year’s primary.) Many <a class="css-yywogo" href="https://www.nytimes.com/2026/05/19/us/politics/republican-senators-trump-paxton.html" title="">Senate Republicans were livid</a> after Mr. Trump endorsed Mr. Cornyn’s opponent last week.</p><p class="css-ac37hb evys1bk0"><strong class="css-8qgvsz ebyp5n10">3. He is a former justice of the Texas Supreme Court. </strong>An alum of the University of Virginia School of Law, Mr. Cornyn served on a state district court in the 1980s before rising to the state’s Supreme Court, the top civil court in Texas. He later served on the U.S. Senate Judiciary Committee, where he <a class="css-yywogo" href="https://www.nytimes.com/2009/06/04/us/politics/04cornyn.html" title="">defended the liberal judge Sonia Sotomayor</a> when Republicans accused her of racism during her U.S. Supreme Court confirmation process. (He <a class="css-yywogo" href="https://www.senate.gov/legislative/LIS/roll_call_votes/vote1111/vote_111_1_00262.htm" rel="noopener noreferrer" target="_blank" title="">voted against</a> her confirmation.)</p><p class="css-ac37hb evys1bk0"><strong class="css-8qgvsz ebyp5n10">4. He helped negotiate a bipartisan gun control law after the 2022 school shooting in Uvalde, Texas, that killed 19 children and two teachers. </strong>The legislation, <a class="css-yywogo" href="https://www.nytimes.com/2022/06/25/us/politics/gun-control-bill-biden.html" title="">signed by Mr. Biden</a>, was the most significant gun control law in the United States in 30 years. Mr. Cornyn’s opponents in the primary have <a class="css-yywogo" href="https://www.nytimes.com/2025/10/06/us/politics/wesley-hunt-senate-texas-cornyn-paxton.html" title="">heavily criticized</a> him for playing a role in the law’s passage.</p><p class="css-ac37hb evys1bk0"><strong class="css-8qgvsz ebyp5n10">5. He led a bipartisan push to overhaul elements of the criminal justice system. </strong>During Mr. Trump’s first term, Mr. Cornyn played a <a class="css-yywogo" href="https://www.nytimes.com/2018/12/18/us/politics/senate-criminal-justice-bill.html" title="">crucial role in the passage</a> of the First Step Act, which reformed punishments for drug offenders and expanded early release programs. “It doesn’t hurt to show some empathy,” Mr. Cornyn said as he sought to <a class="css-yywogo" href="https://www.nytimes.com/2016/01/30/us/politics/senator-john-cornyn-criminal-justice-reform-bill.html" title="">draw Republicans to the cause</a> a decade ago.</p></div><aside aria-label="companion column" class="css-ew4tgv"></aside></div>