AUSTIN — Republican Sen. Ted Cruz and Democratic Rep. Beto O'Rourke are locked in a deadly serious battle to the wire in Tuesday's Senate race.

But occasionally they lighten up.

In the homestretch, Cruz warned of a huge turnout by "the left" and pleaded for conservatives not to stay home.

He'd often paint a word picture of an Election Day tableau in liberal Austin. Hippie Hollow, the nude beach at Lake Travis, would be deserted, Cruz told a well-clothed audience in Tyler late last week. Switching gears, he wisecracked:

"Have y'all ever noticed that at a nude beach, the wrong people always go?"

Listeners guffawed.

In his stump speeches, O'Rourke doesn't ham it up nearly as much.

The El Paso congressman generally stays in what scholars who study political humor say is the safe lane of self-deprecation.

In late July, as he launched a 34-day drive-around during the August congressional recess, O'Rourke warned his fellow El Pasoans that the fall race could get nasty.

"You're going to hear some really terrible things about me over the next three months from the other campaign," he said. Pausing, he added, "Some of it is true."

The hometown crowd roared.

Supporters U.S. Senate candidate Beto ORourke's arrival at a campaign rally on Nov. 2 at Wayne Frady Park in Lewisville. (Chip Somodevilla / Getty Images)

Humor can serve any of several needs a politician might have, according to Jennifer Mercieca, an associate professor of communications at Texas A&M University who studies political discourse.

"It can be used to lighten a heavy moment, build rapport with an audience, lessen awkward moments or topics, or, more meanly, humor can be turned against people or policies, positioning them as objects of derision," she said.

The Dallas Morning News contacted Mercieca and two other humor experts. It provided a half dozen or more examples of jokes told by the dueling Texans in the most expensive — and perhaps highest-profile — Senate race in the country.

Cruz, a fire-breathing populist conservative who's seeking a second six-year term, laces his stump speeches with one-liners and pop culture references.

He's used the third of a four-movie series about dystopia, Mad Max Beyond Thunderdome, to warn that a Democrat-controlled U.S. House under Speaker Nancy Pelosi of California would trigger impeachment proceedings against President Donald Trump and Supreme Court Justice Brett Kavanaugh. Conservatives' recent gains would be reversed, he's warned.

"And by the way, in that story, Beto plays the part of Tina Turner," he told 1,300 people in Longview late last month. In the 1985 film, Turner is Aunty Entity, a corrupt ruler. Many in the crowd laughed.

Cruz's Trumpian style

Dannagal Young, an associate professor of communications and political science at the University of Delaware, said late-night talk show audiences in 2016 liked Trump's disparaging humor.

In 2018, Cruz has retooled it, she said.

"It does seem to be adopting the sort of Trumpish style, right?" Young said. "Kind of way over the top, hyberbolic insults [and] using pop culture references to make analogies that are outrageous but drive home the insult, drive home the point. There's a strategy on Cruz's part."

O'Rourke's wit, revealed sparingly, is less premeditated, she said.

"A lot of the asides that O'Rourke does, the humor is not necessarily designed to advance an argument at all," she said. "A lot of times, it's just an aside."

Ted Cruz supporters hold photos of the incumbent Texas Senator during a Get Out The Vote Bus Tour rally on Nov. 2 in Fort Worth. (Justin Sullivan / Getty Images)

In Tyler late last month, O'Rourke localized his speech, as he often does, with statistics on early ballots cast. Surprisingly, some Texas counties are flirting with the much higher turnout levels seen in presidential election years, O'Rourke said.

Having turnout "we would have in a presidential election year in this state, which historically has ranked 50th" in voter participation is a big deal, he said.

Without missing a beat, he said, "And a quick geography and history lesson: There are only 50 states."

Classic liberal humor

The irony O'Rourke deployed is "classic liberal" humor, said Delaware's Young. She is writing a book about the different psychological outlooks of the left and right in the U.S., and how they affect humor. Conservatives want directness and certainty, while liberals like wordplay and solving puzzles, she said.

In joking about Texas' poor ranking on voter turnout, O'Rourke was being long-winded but playful, Young said.

"Usually when we're talking about irony in political discourse, it's a juxtaposition between what is and what ought to be," she said.

"Liberals do tend to prefer," Young said, "that sort of juxtaposition where you're like, wait, why did he say it as though we don't know this? Oh, we do know this! Oh, I get it!"

Beto O'Rourke supporters follow a live video live feed to keep track of his scheduled arrival at a Nov. 2 campaign rally at Wayne Frady Park in Lewisville. (Chip Somodevilla / Getty Images)

Cruz uses a lacerating wit to skewer O'Rourke. To a Longview crowd, he suggested he'd won the two men's two debates. O'Rourke "seemed kind of shook up," he said.

O'Rourke's TV commercials also come in for scorn.

"Have you seen all the attack ads he's running where he's staring at the camera and sweating and looks like it's a hostage video?" Cruz said to laughter.

O'Rourke humor is never about Cruz. It's more about giving audiences a break from the Democrat's moral earnestness. When O'Rourke recently grew hoarse, midspeech, in Lufkin, press secretary Chris Evans rushed to his side with a bottle of water.

O'Rourke responded to the audience's applause with a line, however goofy, that made listeners applaud even louder:

"Let's hear it for water!"

Texas A&M's Merierca said the Senate hopefuls' lighter side buttresses more serious aims.

"Beto has positioned himself as an earnest and good-natured antidote to the divisive politics of the nation, and Cruz has positioned himself as the voice of Texas conservative conventional wisdom," she said.

One expert unimpressed

Political columnist Walter Shapiro of the Capitol Hill publication Roll Call said he was unimpressed with the samples of Cruz and O'Rourke humor he reviewed.

Shapiro said that was even after watching videos of the speeches to verify that, yes, their audiences lapped it up.

"Nothing either candidate said made me smile, let alone laugh," he said.

Shapiro, who covered 10 presidential campaigns and spent 10 years as a stand-up comic in New York City's "minor clubs," said no modern politicians have been nearly as funny as the late U.S. Rep. Morris Udall, an Arizona Democrat, and former Kansas senator and GOP presidential hopeful Bob Dole.

Shapiro pointed to two examples from the Senate campaign of what he called humor that's mediocre at best.

In one, O'Rourke tells rallygoers an elaborate story about his daughter Molly's blind squirrel. The punch line comes when O'Rourke says the squirrel Tessie's vision has been restored. He said he told Molly, 10, that it might be time to transport the rodent back to its original habitat in East Texas.

"And she said, 'Dad, I'd like to, but I have a life to live,'" O'Rourke recounted.

"Mildly amusing," Shapiro said.

But the joke "fits into the larger category of 'Form B of Self Deprecating Humor,'" he said. "'If you can't be self-deprecating about yourself, use your children as foils.'"

A Cruz aside about pistol-packing Texans also fails to sparkle, Shapiro said.

In Longview recently, after mentioning gun rights, Cruz said, "By the way, I appreciate, when I mention the Second Amendment, y'all not pulling out your guns and shootin' 'em in the air. You know, you get in trouble if you put a bunch of bullet holes in the ceiling. Thank you for your restraint."

Shapiro invoked 92-year-old Las Vegas comedian Shecky Greene to flunk Cruz the comic.

"I'm sorry, I just don't think it's a laugh riot worthy of Jerry Seinfeld to joke about not shooting up the ceiling," he said. "Maybe I have too much reverence for ceilings. But I just don't see Shecky Cruz getting away with this!"