Cornyn is up for reelection next year, and on Monday—the Texas filing deadline—he got a last-minute primary challenger in Steve Stockman, a newly elected member of Congress who prides himself on reactionary outrageousness. Stockman has been calling for Obama's impeachment since shortly after taking office in January and has pushed legislation to investigate Obama's birthplace. He brought Ted Nugent as his date to the State of the Union and raffled an AR-15 for the Fourth of July. When a rodeo clown in Missouri drew controversy for wearing an Obama mask during a bull-baiting routine, Stockman promptly issued a press release inviting him to Texas: "Liberals want to bronco bust dissent," Stockman declared.

This is actually Stockman's second tour in Congress. His first stint came in 1994, when he was swept in with the Newt Gingrich wave—though once in Congress, he deemed Gingrich insufficiently conservative. The Stockman of the '90s styled himself an ally of the then-flourishing militia movement, winning in an upset by accusing a veteran Democratic congressman of supporting the federal raid on the Branch Davidian cult compound in Waco. Stockman later argued that the Waco raid was a government setup designed to create public sympathy for an assault-weapons ban. "These men, women and children were burned to death because they owned guns that the government did not wish them to have," he wrote, in an essay coincidentally published in Guns & Ammo magazine immediately after the 1995 Oklahoma City bombing. In 1996, he was defeated by a Democrat.

Stockman's past is littered with curiosities, as Tim Murphy has recounted in Mother Jones. His wayward youth found him charged with a felony for stashing Valium in his underwear; homeless, he spent several months living in a public park. In the 1990s, Stockman found Jesus and began running for Congress. He finally won on his third try, boosted by support from a direct-mail firm seeking revenge (Stockman's opponent had tried to regulate the industry) and a supposedly independent "newspaper," published from Stockman's home address, that called out government officials as "sodomites" and "mean lesbians." In his current term, Stockman has been dogged by campaign-finance violations and accusations he failed to disclose numerous business ties as required. He was one of 10 House Republicans who refused to vote for John Boehner for speaker, citing "bedrock conservative principle."

Tea Party groups had been clamoring for a challenger to Cornyn. Stockman's candidacy will test how far they are willing to go in their quest for conservative purity. Cornyn has nearly $7 million in his campaign fund; Stockman has $130,000 more debt than cash on hand for his campaign. He filed his candidacy 15 minutes before the deadline and gave an exclusive interview to the website WND, a clearinghouse for birther theories: "We are extremely disappointed in the way [Cornyn] treated his fellow congressmen and ... undermined Ted Cruz’s fight to stop Obamacare," Stockman said. The Tea Party Patriots immediately expressed their support; the Senate Conservatives Fund vowed to "watch the race closely," calling Cornyn "part of the problem in Washington." Both Cruz and the Club for Growth, however, said they would stay out of the race.