Running! is a Teen Vogue series about getting involved in government.

With his left hand on the steering wheel, Congressman Joaquin Castro (D-TX) gestures with his right toward a tiny, worn general store on San Antonio’s poor west side. “We used to go to the store over there a lot,” he tells Teen Vogue, before turning onto Hidalgo Street and motioning toward a bright pink one-story house. “This was a house that we lived in,” the 43-year-old says. “We used to play football in these streets.”

Castro often speaks in the collective: he’ll start a sentence in the first person only to switch, subconsciously and seamlessly, to using “us” and “we.” He can’t help it. As one half of the political phenom known as the “Castro brothers”,” his life, and political fate, have been intertwined with that of Julián, his twin brother’s, since birth.

The allure of this tale of twin brothers raised by a Chicano activist mother in one of the poorest parts of Texas before ascending to the Ivy League and the national political stage is an irresistible iteration of the American Dream. In the telling of that tale, it’s nearly impossible to profile one brother without the other playing the lead supporting role. (“Much to their chagrin,” Jaime Castillo, a former aide to Julián, tells Teen Vogue.)

It was Julián who first captured the country’s attention when he delivered a powerful primetime speech at the 2012 Democratic National Convention. But since Donald Trump’s election in 2016, it’s been Joaquin who has taken center stage. As a member of the House Intelligence Committee, he has fired the alarm regularly — on TV and social media — about the importance of the committee’s probe into Russia’s interference in the 2016 election.

Representative Eric Swalwell (D-CA) who sits next to Joaquin on the Intelligence Committee, says, “Until the transcripts [from the interviews with witnesses] are available, you won’t be able to see just how effective he was. He’s passionate, but he’s not out there throwing bombs and being destructive.”

When Joaquin isn’t questioning Trump associates in the investigation, he’s fundraising for fellow Democrats and angling to win back the House majority for his party come November, when midterm elections will occur throughout the country. He’s not running for governor or the Senate in Texas this year, though he’d been kicking the idea around, but says he still has unfinished business back in his home state.

Joaquin was born in 1974, when the U.S. Supreme Court had ruled just one year prior that education is not a fundamental right. In Texas, that decision was overturned a decade later when members of the Mexican-American community in the Edgewood school district of San Antonio won the fight for equity in school financing. This is the school district — the fourth poorest in Texas at the time (his mother, Rosie Castro, tells Teen Vogue) — where Joaquin’s father, Jesse Guzman, was a teacher. It’s in the area where he and his brother were raised, tagging along to political rallies with their mother.

A well-known activist in her community, Rosie’s political engagement, along with the mighty matriarchal structure of Mexican-American culture (the twins share a last name with their mother and grandmother) laid a strong foundation for Joaquin’s passions.

The boys were raised by their mother and grandmother, Victoria, an orphan who immigrated as a young girl from Mexico (their parents, who were never formally married, separated when the twins were children). For a long time, Joaquin didn’t know whether his grandmother was documented or not, a fact he cites as influencing his unwavering determination to protect DREAMers, or individuals protected by the Deferred Action Childhood Arrivals policy, who were brought to the United States at an early age without documentation.