The old saying that the most dangerous place in Washington is between Sen. Charles E. Schumer and a camera? New evidence suggests otherwise.

“I didn’t want to ruin the film,” the New York Democrat said about turning down an offer to play himself in the new movie “Megan Leavey.”

The film, which stars Kate Mara as the titular character, is based on a real story about a Marine dog handler and her relationship with her canine bomb-sniffing partner, Rex. The two navigate the perils of the Iraq war and, later, the federal bureaucracy, after both are injured in combat.

In real life, New Yorker Leavey reached out to her senator for help when she sought to adopt Rex after he retired following tours of duty in Iraq and Afghanistan.

“I was really proud to play a small role. I’m not the hero. I’m just the expediter,” Schumer told an audience at Washington’s E Street Cinema at a screening of the feature. The senator spread the word to people supporting Leavey’s adoption by helping circulate petitions that garnered thousands of signatures.

This is the first feature film for the movie’s director, Gabriela Cowperthwaite. Her previous movie, the documentary “Blackfish,” helped facilitate a national conversation about the appropriateness, and hazards, of keeping killer whales in captivity at facilities such as SeaWorld.

The challenges of directing both humans and dogs in a war movie were a big concern for her, and she wanted to retain some of the immediacy of documentary filmmaking in this new project.

“What I wanted to bring into this was its authenticity. There’s a spontaneity that comes with documentary,” she said after the preview screening on May 23. “You need to be rolling, because when the dog does ‘the thing,’ I promise you it won’t happen again.”

As far as Schumer is concerned, it all came together.

“I can’t tell you how thrilled I am that you turned this story into film,” he told the filmmaker and her producers. And that’s even with veteran actor Andrew Masset, whose credits include roles in films such as “Kill the Messenger” and television shows such as “Days of Our Lives” and “Halt and Catch Fire” portraying him. 

Mara is no stranger to Washington herself. In addition to her appearance in “Megan Leavey” outside the Capitol with Masset and her time on the Netflix series “House of Cards” as reporter Zoe Barnes, the actress was in D.C. on Wednesday to argue for more transparency at the Agriculture Department regarding its records of inspections and violations of the Animal Welfare and House Protection acts. 

“Megan Leavey” comes out in wide release in theaters on Friday.