Even happier than Sen. John Cornyn (R-Tex.) is House Republican leadership: The whacky Rep. Steve Stockman is leaving the House, where he’s become a cartoonish gadfly, to become Cronyn’s only primary challenger. A Capitol Hill Republican wisecracked, “Stockman is the biggest nut in the squirrel’s nest.” Stockman is sufficiently nutty that even the right-wing groups who backed people like Christine I’m-not-a-witch O’Donnell are staying away, as Politico reported. (“He is an unabashed provocateur who raffled off a Bushmaster assault rifle  during this year’s gun control debate and once said that the great thing about  planet Earth is that ‘if you poke holes in it oil and gas come out.’ In an 1,100-word campaign manifesto released Tuesday, Stockman called himself  ‘the most fearless conservative in Congress’ and warned conservative supporters that ‘liberal John Cornyn’ was seeking to put a ‘Republican bayonet in your  back.’ “)

Sen. John Cornyn (Rod Aydelotte/Associated Press via Waco Tribune Herald) Sen. John Cornyn (Rod Aydelotte/Associated Press via Waco Tribune Herald)

How off-the-balance-beam is Stockman? A Texas outlet reminds us that “in the mid-’90s . . . he was voted out of the House of Representatives after a single term for, among other things, opining that the government’s 1995 siege of the Branch Davidian compound in Waco was staged to gin up support for an assault weapons ban and saying Attorney General Janet Reno was guilty of ‘premeditated murder.’ ” In January, my colleague Dana Milbank summed it up:

In addition to his threat to seek impeachment of President Obama if he issues executive orders on guns, he voted “present” rather than cast his ballot to elect John Boehner speaker, complaining that the Republican leader cooperated with “a liberal White House that has outmaneuvered him at every turn.” He also introduced legislation that would end gun-free zones around schools.

By his own account, Stockman spent time homeless as a young man, sleeping in a Fort Worth park, looking for food in trash cans and going by the street name “Max.” He has been jailed more than once, he has said in interviews, and was charged with a felony after one such incident when authorities found Valium in his pants; he said a girlfriend put the pills there, and the charge was later reduced. . . . In his brief but glorious term, Stockman established daily prayer meetings in his office and tangled with the Anti-Defamation League for speaking on a radio program of a group that the ADL called anti-Semitic. Midway through his term, he launched an effort to investigate the first Kinsey Report and to cut off federal funding for sex-education programs that might be based on the landmark study.

You sort of wonder if the House leadership isn’t popping champagne corks. Remember this is the guy  who tweeted in April, 2013, “Our campaign bumper sticker: If babies had guns, they wouldn’t be aborted.” And to top it off, the Houston Chronicle has reported “that he violated federal ethics laws by failing to disclose a series of business affiliations, while providing no details about the business he said was his only source of income.”

Stockman, however, is simply the most comical and extreme contender among a crop of tea party-inspired challengers who don’t exactly reflect well on the anti-incumbent forces who like to shout “betrayal” each time a harebrained scheme is shot down. So why is it that of all the challengers, only Mississipi state Sen. Chris McDaniels passes the laugh test?

It is hard to escape the conclusion that the tea party is becoming the province of cranks, outside money-makers like Jim DeMint and Heritage Action and ratings-starved right-wing talk radio. Without anything more than claims of perpetual victimhood and an ethos that equates “true conservatism” with outrageousness, the tea party risks becoming a fringe gaggle, a political punch line. If all of the tea party challengers lose, what’s the future of the tea party and outfits like the Senate Conservatives Fund? Even the most politically extreme donors may recoil at the notion that their money is being used for nothing more than primarying mainstream candidates with unserious, ill-prepared radicals.

Having blown multiple Senate seats in 2010 and 2012 and led the party into the shutdown debacle, the tea party as a discrete movement is skating on the edge of irrelevancy. Across-the-board losses in 2014 might well seal its fate. Once it loses even the patina of legitimacy, the money dries up and incumbents are free to ignore tea partiers.

There will still be staunch conservatives and still be those who favor confrontation over compromise. But the energy will be sapped from destructive infighting, political fantasizing at the expense of political victories and inside-the-Beltway opportunism by those who profit from attacking other Republicans. That would be to the good of the country, the Congress and the GOP.