MAGA’s top lawyer just gave a sitting GOP senator the biggest scare of his career

Tuesday’s Senate Republican primary in Texas ended in an anticlimax, with no candidate winning a majority of the vote. Incumbent Sen. John Cornyn will face state Attorney General Ken Paxton in a May 26 runoff.

Though Cornyn will likely receive more votes than the other two Republican candidates — as of this writing, Cornyn has 43 percent of the vote, compared to Paxton’s 40 percent — Cornyn faces a tough road if he hopes to save his political career. Veteran senators (Cornyn was first elected in 2002) typically don’t face serious challengers within their own party. And the bottom line is that most Texas Republican voters just voted to make someone other than Cornyn their senator.

Paxton’s strong performance, moreover, is a triumph for a far-right legal movement that seeks to reshape how the US Constitution is interpreted — one that rejects the liberal democratic theory of the Constitution that rose to prominence in the 1960s, and that approaches legal interpretation through a more partisan lens. 

This includes challenging election results. As Texas AG, Paxton brought Texas v. Pennsylvania, a lawsuit seeking to block President Joe Biden’s victory in the 2020 election. 

Beginning in the Obama administration, the Texas Attorney General’s office became a prolific source of federal lawsuits challenging Democratic policies, and this practice accelerated once Biden took office. Paxton claims that he sued the Biden administration 106 times as Texas’s top legal officer, filing the final lawsuit just hours before Biden left office.

To be sure, Paxton did not single-handedly build the Texas Attorney General’s office into the nation’s most important Republican law firm from the ground up. The office began asserting itself as a Republican Party litigation shop under Paxton’s predecessor, now-Gov. Greg Abbott, who, among other things, successfully sued the Obama administration to block a program that would have allowed millions of immigrants to work and remain in the United States.

But Paxton, who succeeded Abbott in 2015, took over the state AG’s office shortly before Donald Trump started transforming the Republican Party into a vehicle for anti-immigration policies and his own agenda. And, because the Texas AG’s office so frequently advances Republican legal positions in court, that means that Paxton played an enormous role shaping the Trump-era GOP’s legal strategies and arguments.

Republican Party officials still sometimes split on important legal questions — just look at the Supreme Court’s recent decision striking down many of Trump’s tariffs. As leader of one of the Republican Party’s most important sources of legal power, Paxton did as much as any other lawyer to move the party’s legal arguments in Trump’s direction and advance a distinctly MAGA approach to the law.

Why Texas brings so many cases seeking to advance Republican causes

It makes sense for the GOP to concentrate its litigation resources in Texas, regardless of which Republican controls the state AG’s office. Texas is a big state, with nearly 750 lawyers working under Paxton, so it can afford to divert a few — or even a few dozen — of these lawyers into partisan legal work. And two unusual features of Texas’s federal court system make Texas attractive to Republican plaintiffs.

One is that Texas federal courts often permit plaintiffs to select the trial judge who will hear their case. Republican litigants often take advantage of these courts’ permissive approach to judge-shopping to obtain favorable court orders. Think of Judge Matthew Kacsmaryk, the Christian right activist who anti-abortion lawyers selected because he would grant their request to ban the abortion drug mifepristone (the Supreme Court unanimously reversed Kacsmaryk, holding he lacked jurisdiction over the case).

Texas federal cases also appeal to the United States Court of Appeals for the Fifth Circuit, which is dominated by judges closely aligned with the MAGA movement. Texas, in other words, is one of the few places where a plaintiff filing a federal lawsuit can expect their case to be heard by judges who are even more sympathetic to the Republican Party than the current Supreme Court.

Paxton neither appointed these judges, nor did he set the rules allowing his office to often choose which trial judge would hear his lawsuits. But he’s taken full advantage of the sympathetic judges who often hear his cases. And his office has long been an incubator for MAGA legal talent.

Indeed, if Paxton prevails in the November general election, all three of Texas’s top elected jobs will be held by Republicans who cut their teeth as part of the Texas AG’s litigation machine. Abbott ran the AG’s office before Paxton. And Texas’s other senator, Republican Ted Cruz, spent five years as Abbott’s solicitor general.

It’s also fairly likely that Texas’s distinctly MAGA approach to legal interpretation will gain a seat on the Supreme Court. Two Fifth Circuit judges, James Ho and Andrew Oldham, are alumni of the Texas attorney general’s office, and are widely considered leading contenders for a Supreme Court appointment in Trump’s second term. Both men frequently embrace legal positions that are well to the right of the current Supreme Court.

How Paxton pushed fringe legal ideas into the mainstream

The Supreme Court’s rightward drift under Trump, combined with the Fifth Circuit’s even more aggressive lurch to the right, appears to have emboldened Republicans throughout Texas’s government. These courts enabled Paxton to shut down much of the Biden administration’s immigration policies for months at a time. And they emboldened the state legislation to enact numerous bills that clearly violated the Constitution, as least as the Constitution was understood when they were enacted.

Because Paxton’s office was generally charged with defending these bills, that meant that his office often argued for avulsive constitutional change. And he succeeded fairly often.

Before Roe v. Wade was overruled in 2022, for example, Texas enacted SB 8, which effectively banned most abortions by allowing private bounty hunters to collect large sums of money from abortion providers. Paxton’s office was one of several teams of lawyers who persuaded the Supreme Court to immunize SB 8 from any meaningful judicial review.

Indeed, the Court’s decision in Whole Woman’s Health v. Jackson (2021) is potentially one of the most consequential constitutional decisions in the Court’s history. If taken seriously, the Court’s reasoning in Jackson would allow any state to neutralize any constitutional right by deploying bounty hunters against anyone who tried to exercise that right — although, realistically, it’s unlikely that the five Republican justices who signed onto Jackson would follow their own decision in a case that didn’t involve abortion. 

Similarly, in Free Speech Coalition v. Paxton (2025), Texas enacted an anti-pornography law that was virtually identical to a federal law the Supreme Court struck down in 2004. Yet, rather than apply their previous decision, Paxton’s lawyers successfully convinced the Supreme Court to abandon that 2004 decision and uphold the state law.

Paxton also frequently lost in the Supreme Court. Texas v. Pennsylvania, Paxton’s attempt to overturn the 2020 election, went nowhere. The Court also rejected a clearly unconstitutional Texas law in Moody v. Netchoice (2024), where the state’s Republican legislature attempted to seize control of content moderation at major social media platforms like Twitter, Facebook, or YouTube.

In other cases, Paxton’s office secured temporary victories from the Supreme Court, before losing many months later. In Biden v. Texas (2022), for example, Paxton got Kacsmaryk to reinstate a Trump-era border policy that the Biden administration eliminated. Although the Supreme Court eventually reversed Kacsmaryk, scolding him for imposing “a significant burden upon the Executive’s ability to conduct diplomatic relations with Mexico,” it sat on the case for nearly an entire year — allowing Kacsmaryk to function as the United States’ de facto border czar for that entire period.

Similarly, in United States v. Texas (2023), Paxton’s office selected a MAGA-aligned judge named Drew Tipton to block a Biden administration memo instructing Immigration and Customs Enforcement to prioritize immigrants who “pose a threat to national security, public safety, and border security and thus threaten America’s well-being.” Tipton’s decision was illegal, because a federal law provides that the Secretary of Homeland Security, and not Tipton, “shall be responsible” for “establishing national immigration enforcement policies and priorities.”

Once again, however, Paxton’s office effectively convinced the Supreme Court to leave Tipton’s order in place for 11 months, before the justices eventually reversed him.

These are just a small sample of the most politically significant cases handled by Paxton’s office — again, the Texas AG filed more than a hundred different federal lawsuits just against the Biden administration. But they are indicative of the aggressive approach Paxton brought to federal litigation. His office took dubious legal positions. It brought lawsuits that contradicted the explicit language of federal laws. It even sought to overturn a presidential election. 

Paxton’s office, in other words, was an incubator for some of the most aggressive legal theories to emerge from the conservative legal movement in the last decade. And, with sympathetic judges on his side, Paxton won these cases surprisingly often.