Rep. Steve Stockman (R-Tex.) isn't known for being shy about his opinions. He sounds off on everything from gun control to the Constitution. Here are some of his most memorable moments. (Julie Percha/The Washington Post)

Rep. Steve Stockman — a Republican primary challenger to Sen. John Cornyn of Texas — might be the closest thing in this election year to a middle finger running for the U.S. Senate by itself.

“If babies had guns they wouldn’t be aborted,” says a Stockman campaign bumper sticker.

“The best gun lubricant around,” read a posting on Stockman’s campaign Twitter feed. It was accompanied by a photo of an assault rifle and a spray can marked “Liberal Tears.”

“For every gift of $10 you make right now,” Stockman promised on his Web site, “I’ll send you one of my Obama Barf Bags.”

This man is running for the Senate in a state with 26 million people. By conventional measures, he is not doing it well. One recent poll had him down by 44 points. Also, of the 12 groups listed under “past and present endorsements” on Stockman’s Senate campaign site, as of Friday at least seven had not actually endorsed him for the Senate.

Another “endorsement” is attributed to Howard Phillips, a conservative activist who died seven months before Stockman got in the race.

But Stockman seems to be betting — again — on his talents for nation-scale insult comedy, for grabbing free publicity with over-the-top attacks on the hard right’s enemies.

That is his best hope now in a campaign without enough money, friends or time.

“His decision was a last-minute one, and it was because nobody else that was credible had stepped up to the plate” to challenge Cornyn, said David Bradley (R), a longtime friend of Stockman’s and a member of Texas’s elected State Board of Education.

But Bradley said Stockman has been counted out before in a remarkable life that included a period when Stockman lived homeless in a Fort Worth park.

“People underestimate him,” Bradley said. “And, amazingly, he wins.”

Stockman — who returned to Congress last year after serving one term in the 1990s — could not be reached for comment this past week. Donny Ferguson, who is a spokesman for Stockman’s House office on Capitol Hill and his Senate campaign, declined to comment in an e-mail message.

“Sorry I’m unable to get back to you but we are very busy talking with voters,” Ferguson wrote. After The Washington Post inquired about problems with the endorsements list, Ferguson said the information was being updated, and on Saturday the endorsements page had disappeared.

Stockman’s biggest news this past week was made not from Texas but from Wall Street — he appeared in a video set in New York, touting the virtual currency Bitcoin.

Stockman, 57, in his total of three years in Congress, has passed just one piece of legislation, a noncontroversial measure to allow the “Washington for Jesus” rally to take place on the Capitol grounds in 1996.

But he holds a place in the Hill’s modern lore as an innovator in the art of shock politics. Stockman has now been the wild-man newcomer of two different House classes, 18 years apart.

In 1994, Stockman ran for office as a political novice, with a bootstrap story that began with his time living in Fort Worth’s Water Gardens park (“I called myself ‘Max,’ ” he told the Philadelphia Inquirer in 1995, “because I figured this was the maximum I could go down.”) He managed to unseat Jack Brooks (D-Tex.), a longtime congressman, in one of the biggest surprises of Newt Gingrich’s Republican rout.

In that first stint in Congress, Stockman became infamous for his conspiracy theories about gun control. He contended, for instance, that the 1993 federal raid on the Branch Davidian compound in Texas was staged by the Clinton administration as a political gesture to bolster the case for an assault-weapons ban.

In 1996, Stockman lost to a Democrat.

Then, in 2012, somehow he was back.

In a low-turnout primary, Stockman traded on his lingering name recognition with “Re-elect Congressman Stockman” yard signs (which did not mention that he had last been “Congressman Stockman” in January 1997).

He made the GOP primary runoff with 11,800 votes. He won the runoff with 21,500, effectively locking up a Republican-leaning district with 533,000 people of voting age.

This time around, Stockman has made a name with attention-grabbing stunts — he invited rocker Ted Nugent to the State of the Union address after Nugent said that he would wind up dead or in jail if President Obama was reelected — and flash-point rhetoric. Stockman has made the case for impeaching Obama over his gun policies and trolled liberals on Twitter: “The best thing about the Earth is if you poke holes in it oil and gas come out.”

“People always underestimate him, because he likes sort of a down-home approach to expressing himself,” said Rep. Dana Rohrabacher (R-Calif.), the one sitting member of Congress who Stockman says has endorsed him in the Senate primary. Rohrabacher shares Stockman’s ­unusual-everyman style — at the time he was being interviewed by phone, Rohrabacher said he was trying on pants at a Goodwill store.

But at times, Stockman’s rhetoric has provoked outrage — and embarrassed many other Republicans. In October, for instance, a chorus of conservatives was complaining about the shutdown-
related closure of the National World War II Memorial.

But Stockman found a metaphor ugly enough to set him apart.

“Democrats are curb-stomping veterans,” he wrote, alluding to the act of smashing someone’s head against a curb.

In Texas, Republicans thought Stockman might keep his new seat for years. But then, just minutes before the Dec. 9 filing deadline, Stockman announced he would give up his House seat and run for the Senate against Cornyn.

Stockman’s model, of course, is Sen. Ted Cruz (R-Tex.), who defeated an establishment candidate last year with an appeal to the Lone Star State’s conservative grass roots.

There’s just one glitch: He is not Ted Cruz. He is not even endorsed by Ted Cruz.

Cruz had strong backing from big-spending outside groups, which paid for pro-Cruz ads in Texas’s large and expensive TV markets. Stockman does not. He appears too much of a long shot, even for people who bet on long shots.

“John Cornyn owes it to the voters in Texas to explain why he has voted for bailouts, debt-limit increases and higher taxes,” said Matt Hoskins of the Senate Conservatives Fund, which is backing challengers to Sens. Mitch McConnell (R-Ky.) and Thad Cochran (R-Miss.). But, in Texas, “we have not endorsed anyone in the race,” Hoskins said. “There are other people in this race as well. Stockman’s not the only candidate.”

Another difference: Cruz had spent more than a year cultivating relationships with conservatives across the state, meeting with them in small groups and one-on-one. Stockman, since he announced, has not even met with the tea party group based just miles from his house in the Houston suburbs.

“You need a scrapper. . . . We almost need WWE fighters” in the Senate, said Michael Openshaw, the co-founder of another tea party group in North Texas. He has met with Cornyn’s staffers and with 32 other candidates for various Texas offices. But not Stockman. “Is Stockman the guy? . . . I haven’t seen him out there publicly making the case enough.”

Another problem for Stockman has been a series of complaints about campaign violations. This fall, the Houston Chronicle reported that Stockman fired two House staffers after they made improper donations to his campaign. Stockman also faced campaign finance inquiries in his first term.

In the recent poll, Cornyn was reportedly at 50 percent. Stockman was at 6, followed by other challengers. Stockman’s allies say they still see a path to victory there; if Stockman can force a primary runoff, a one-on-one showdown with Cornyn, then maybe he would have a chance.

But others in Texas are already wondering if the campaign is one of Stockman’s troll jobs — this time designed to provoke his friends instead of his enemies. What if he is running not to win but rather to rope in some donations and pay off the $163,000 in debt he has left over from past campaigns?

“You can be unusual. But then it goes into, are you insane? I don’t think he’s insane,” said Matt Mackowiak, a Republican consultant and co-founder of the political blog Must Read Texas. “This thing doesn’t make sense to me, unless it’s a debt-retirement operation.”