Filmaker and FRONTLINE producer Michael Kirk joined Boston Public Radio on Monday to speak about FRONTLINE's upcoming film "Zero Tolerance." The film looks at the origins of President Donald Trump's immigration policy and rhetoric.

Trump's success at running on the immigration issue was planned and crafted for years before, Kirk said.

"[It was due to] the audaciousness of three political outliers in Washington: Steve Bannon, Jeff Sessions, and his communications aide, Stephen Miller," Kirk said. "They all get together one night and have a plan to change the Republican party, to move Fox News more to the right and to elect a president of their choice who will carry their hard right immigration message to the American people."

FRONTLINE's film Zero Tolerance premieres October 22 at 10/9c on PBS and online.