Premiering on PBS Tuesday October 20 at 10pm [please check local listings] as a co-presentation of Independent Lens and FRONTLINE, the new documentary Immigration Battle plunges straight into the heart of one of the most divisive issues in America.

Filmmakers Michael Camerini and Shari Robertson chronicle the struggle to create meaningful immigration reform over the course of more than 15 years. The duo’s previous work, How Democracy Works, was an ambitious 12-part series shot during the Bush administration about the “commitment to change the way that the United States handles the bedrock national identity issue of immigration.” More than a decade later, as we witness in their new film, the struggle for change continues.

Immigration Battle is a fly-on-the-wall look at the high-stakes effort to broker a deal in Congress — an effort led by Rep. Luis Gutierrez (pictured above; D-IL), a mover and shaker who makes his party nervous for fear that he’s more loyal to immigrants than Democrats. Immigration Battle follows Gutierrez as he leads the movement on the outside while secretly negotiating across the aisle inside Capitol Hill.

“I feel like I’m sneaking around on my party when I have dinner with you guys!” he says, referring to his meetings with Rep. Mario Díaz-Balart (R-FL), with whom he strategizes about how to build support across party lines. In addition to Gutierrez, Díaz-Balart, and their staffs, we meet Mick Mulvaney (R-SC) — a Tea Party member who communicates with his Spanish-speaking constituents in their own language, and who chastises members of his party for taking a political approach that “takes the entire Latino community and writes them off.”

Immigration Battle chronicles this constellation of politicians from January 2013 forward as they work to make the case for immigration reform against looming deadlines and within political minefields. The film reveals just how close Congress came to passing a bipartisan immigration reform bill before President Obama’s executive action in November of 2014 redrew the battle lines.

Complete with dramatic highs and lows, from deal-making over secret dinners to walk-and-talk hallway negotiations right out of The West Wing, the film is an unforgettable window into modern policymaking.

As we head into a big presidential election year, clearly immigration will remain a hot-button issue. This new documentary will help every voter sort out how we got here and where we may be going, even as the battle line remains firmly drawn in the sand.