What’s it like to have a consummate romance spanning 30 years? Screenwriter-director Ron Nyswaner has been writing films for more than four decades, earned an Oscar nomination for Philadelphia and worked on critically acclaimed series like Ray Donovan and Homeland . And now, with Showtime’s limited series Fellow Travelers , Nyswaner makes his television debut.

Based on the novel by Thomas Mallon, Fellow Travelers is a sweeping, tragic love story and political thriller that chronicles the secret romance of two very different men who meet in the shadow of McCarthy-era Washington. Matt Bomer plays Hawkins Fuller, a man with a successful career in politics who generally avoids emotional entanglements—until he meets the idealistic Tim Laughlin (Jonathan Bailey). The two begin a romance just as Joseph McCarthy and Roy Cohn declare war on "subversives and sexual deviants," ushering in one of the darkest periods in 20th-century American history. Over the course of three decades, we follow the pair as they cross paths through the anti-Vietnam War protests of the 1960s, the drug-fueled disco hedonism of the 1970s, and the AIDS crisis of the 1980s, all while encountering obstacles in the world and within themselves.

Here, Nyswaner talks about the long road he took to adapt the novel into a film, the changes he made to the book, and the importance of queer representation on television.

DEADLINE: How did you come across this book by Thomas Mallon and when did you start working on the film adaptation?