Beto O’Rourke’s launch of his presidential campaign on Thursday became more a call to arms — his constantly gesticulating ones — than the message he wanted to convey. Perched on a chair in an Iowa coffeehouse — and later, from atop the counter of another one — O’Rourke presented an athletic drill of upper-body movements that might exhaust a pep squad: pointing, fist shaking, arms crossing and Bob Fosse-like jazz hands.

President Trump, no slouch in the art of exuberant hand gestures, mocked the former congressman and El Paso city councilman. “I’ve never seen so much hand movement,” he told reporters at the White House. “I said, ‘Is he crazy, or is that just the way he acts?’ I’ve actually never seen anything quite like it.”

Late-night hosts feasted on O’Rourke’s physically expressive entrance into the crowded Democratic race, offering a buffet of slights of the Texan’s hands. They also ripped into Trump for criticizing O’Rourke for something the president has perfected.

Nonverbal communication matters. It often matters far more than the words being uttered, according to specialists. A candidate can say little, but the body never stops talking.

So, do distinctive, potentially distracting gestures like O’Rourke’s help or hurt a politician? Experts say it depends on whether the (often subconscious) movements match the message.

“It’s usually not a detriment, but an addition,” said Carol Kinsey Goman, an authority on body language. “If we can’t see a person’s hands, we tend to distrust them. I don’t think I’d want to tamp his enthusiasm.”

Lyndon B. Johnson was an epic pointer, even though every child is told not to do that. He used his body as a blunt instrument, invading other politicians’ personal space to assert his power. Teddy Roosevelt was a pointer, too, and a serial hat doffer.

Addressing massive crowds of the faithful, Adolf Hitler and Benito Mussolini weaponized their hands, punching and finger wagging, to choreograph their exhortations.

Winston Churchill is known for the V-for-victory sign. Richard Nixon famously inverted its meaning — V for vanquished — before his final helicopter ride from the White House lawn. Bill Clinton punctuated speeches with a fist, topped with a thumb extended, compressing his lips inward until they disappeared. Al Gore, who was frequently criticized for his stiff delivery, even his clapping, often appeared as if he had rented his body and it was a bad fit.

In the 19th century, long before microphones and sound bites, and when politics was a blood sport, oratory was an art form, and a very physical one. “It was like watching a silent movie, where you have to be dramatic and more conscious of your physical movements,” historian Joseph Ellis said.

Politicians need to gesture with their hands and arms, according to anthropologist David Givens, director of the Center for Nonverbal Studies. “It shows conviction,” he said, “and that they believe in what they’re saying. It’s an assertion that ‘I am here. Pay attention to me.’ Using hand gestures with language is used by humans around the world.” Most people believe they can read nonverbal communication, Givens said. “We think we can look at you and read you. Sixty-five percent of the meaning people take away from an exchange comes from the nonverbal.”

Expressiveness can be an advantage, he added. “Deceivers typically omit hand gestures. They withhold information,” Givens said, like poker players.

Patti Wood, a speech coach and expert on body language, said that in recent elections, “The candidate that’s running for the presidency with the biggest, broadest gestures tends to win — the alpha male.” Trump over Hillary Clinton. Barack Obama over Mitt Romney, who often appeared wooden. “The hands come out from the heart,” she said. “They communicate emotion.” They can help improve speech. “Gesturing helps you remember and reduces speech imperfections and pauses. Symbolically, it’s like opening file drawers,” she explained.

But experts also caution that, in politics, excessive nonverbal expression can sometimes overwhelm the words. Brett O’Donnell, a message and media strategist who has coached Republican candidates for debates, including President George W. Bush and Sen. John McCain of Arizona, characterized O’Rourke’s performance as “frenetic” and “trying too hard.”

“It looked like he was doing semaphores and flagging down airplanes,” O’Donnell said. “Good delivery should be natural and not call attention to itself. If it reinforces the message, it’s good delivery.”

Also, what works in one part of the country, like Texas, may not play well in more subdued Iowa.

O’Donnell, who coached Bush not to slump and sigh after his first 2004 presidential debate with John F. Kerry, said O’Rourke’s problem can be fixed. The question, O’Donnell said, is: “Does he want to fix it?”

Authenticity is crucial to winning voters, according to former Democratic political consultant Robert Shrum, a veteran campaign strategist who worked on the Gore and Kerry presidential bids. “When you talk about coaching people, you can’t make them who they’re not,” Shrum said. “It’s so clear this kind of gesturing is part of O’Rourke’s communication pattern. JFK was constantly gesturing, pointing his finger. So does almost everybody who is an effective communicator. If you try to make O’Rourke into something else, he would lose his authenticity, and he would become very self-conscious.”

But optics matter, especially in debates. Before the first 2000 debate between Gore and Bush, Shrum recalled, “We told Gore not to react to Bush and not to argue with the moderator. Gore won the debate massively on substance but lost on atmospherics.”

Gerald Shuster, who teaches political communication and presidential rhetoric at the University of Pittsburgh, said of O’Rourke’s arms, “If they become too distracting, any idiosyncrasy perceived by the audience is a negative.” Still, Shuster added, “I don’t think Beto wants to walk away from who he is. Without a solid base, it doesn’t get him anywhere.”

O’Rourke’s passion, his youthful energy, is what excited his base. His arms are a natural expression of his zeal. Cory Booker, Shrum pointed out, is a dramatic gesticulator. Bernie Sanders’s hands can also be as animated as his rhetoric. Elizabeth Warren is partial to short, choppy hand motions.

As for Trump’s mockery of O’Rourke, though the president can match a Queens cabdriver in his penchant for manual balletics, Shuster said, “The president may have well been trying to create the distraction purposely. He’s calling attention to the movement and the nonverbal rather than the message.” Trump, for his part, has upended the nonverbal playing field, much like he has almost everything else.

Experts caution that some of O’Rourke’s gestures in Iowa were discordant with his speech. “He’s using gestures that don’t have a physical representation of what he’s talking about. A fist, bringing the finger down and pushing his hands down instead of up have almost exactly the opposite effect from what he’s trying to convey,” Wood said.

The problem with O’Rourke’s Iowa appearances, Goman said, is that his gestures too often rise above his shoulders. “You start to look erratic,” she said. “You should keep your gestures lower than your shoulders. If I was coaching him, I would try to minimize his gestures.” Of course, she noted, “He will be more self-conscious about this whether he’s coached or not.”

Ellis called O’Rourke’s gestures a measure of his enthusiasm. “That’s an expression of his message. Anyone who stays perfectly calm and perfectly motionless should be disqualified from any debate.”

“Maybe this will be the era of the passionate gesturer,” Goman said. “I can’t wait for the debates. It’s going to be wild.”

Correction: An earlier version of this story incorrectly referred to Beto O’Rourke as a former El Paso mayor. He is a former El Paso city councilman.