Democrat Tom Sullivan of Centennial plans to take on House Assistant Minority Leader Cole Wist, R-Centennial, in November, he announced Monday.

Sullivan, the only Democrat in the House District 37 race so far, ran for state Senate against incumbent Jack Tate in 2016, losing by about 7 percentage points.

The south-metro Denver district includes Centennial, Foxfield, Inverness and parts of Aurora and Englewood. Sullivan noted that Democrats Hillary Clinton and Sen. Michael Bennet won the district in 2016

Sullivan cited gun bills sponsored by Republicans this session. Sullivan’s son, Alex, was one of the victims of the Aurora theater shooting in 2012 that left dead and 70 wounded.

He’s been a powerful advocate for gun-safety laws since.

“You can raise money for somebody. You can make empowered speeches, but when it comes down to it, you don’t really have the ability to make the change unless you’re the one up there making the vote,” he said in a statement. “That’s what I have to do.”

He noted that Wist has an A rating from the National Rifle Association.

“I’m doing this for my murdered son Alex, but I’m also doing this because I know that we can do better for my daughter Megan and everyone in Colorado who needs someone to fight for regular people and not protect the well-connected political insiders,” Sullivan said.

His other top priorities as a lawmaker would include affordable housing, transportation funding, a quality education system and support for veterans.

He is an Air Force veteran and former U.S. Postal Service worker.