To understand what makes Democratic presidential candidate Beto O’Rourke tick, you have to understand his favorite band, the Clash. When a friend at El Paso High gave him the band’s seminal 1979 double album, “London Calling,” O’Rourke said, “it absolutely changed my life.”

“The urgency in that music. Politics in a way I had never experienced it before. (Lead singer/songwriter) Joe Strummer — the coolest human being that ever walked the planet,” O’Rourke, the former Texas congressman, told The Chronicle’s “It’s All Political” podcast.

“Selling (1980 triple album) ‘Sandinista!’ for the price of a single album. Wearing their politics on their sleeve. Trying to be a voice for those who otherwise would not have a voice — but then making it popular. Bringing me in through the beat, the riffs, (guitarist/singer/songwriter) Mick Jones’ soaring vocals. They just absolutely changed my life.

“There’s got to be something in this corporate moment where it’s not just what we watch on TV and what we buy,” O’Rourke said. “It’s our politics — it’s how we consume public life.”

The “London Calling” song “Clampdown” has become O’Rourke’s campaign theme song — he used as walk-up music at the recent California Democratic Party convention in San Francisco and on Sunday at the Iowa Democratic Party’s annual Hall of Fame dinner that 19 candidates attended. In September, O’Rourke is believed to have been the first candidate to drop a Clash reference during a U.S. Senate debate when he accused his GOP opponent, Texas Sen. Ted Cruz, of “working for the clampdown and the corporations and the special interests.”

The song is about how “you can grow up idealistic with the best of intentions,” O’Rourke said. “ But you can be compromised or corrupted or consumed by these larger forces and powers.”

And it is about the failures of the capitalist system and government crackdowns on protesters in the 1970s in the United Kingdom and elsewhere.

You grow up and you calm down

You’re working for the clampdown

You start wearing the blue and brown

You’re working for the clampdown

So you got someone to boss around

It makes you feel big now

You drift until you brutalize

Make your first kill now

“And some of the lines in that song where they’re talking about being afraid of somebody because of their differences,” O’Rourke said, then quoting the song’s opening line: “Taking off his turban, they said, is this man a Jew?”

“It’s just chilling for me to even say that,” O’Rourke said. “But we say that during an administration that has sought to ban all Muslims from traveling to the United States of America. Or has called Mexican immigrants ‘rapists’ and ‘criminals’ or asylum-seekers ‘animals’ or ‘an infestation.’ ”

“The Clampdown is upon us and sometimes we are tempted to laugh it off,” O’Rourke said. “’Who is the clown in the White House saying this ridiculous stuff?’”

In these days of evil presidentes

Working for the clampdown

“I feel like that song is so prescient.,” O’Rourke said. “It wasn’t just reminding us of bad things that had happened before — it was a warning about the things to come. And we are at that moment. So I think that song, for me, really resonates at this moment.”

O’Rourke isn’t the only candidate featuring the the Clash. New York Mayor Bill de Blasio used “Rudie Can’t Fail,” another song on “London Calling,” at the Iowa dinner Sunday. But that song is decidedly less political. It’s about a young man rebelling about being told to grow up. And it doesn’t exactly look good for the candidate.

How you get a rude and a reckless?

Don’t you be so crude and feckless

You been drinking brew for breakfast

Rudie can’t fail (no, no)

Joe Garofoli is The San Francisco Chronicle’s senior political writer. Email: jgarofoli@sfchronicle.com Twitter: @joegarofoli