George Conway, former conservative lawyer and ex-husband of President Trump’s former Senior Counselor Kellyanne Conway, has filed paperwork to run for Congress in New York City as a Democrat.

The announcement comes as Conway seeks to replace Rep. Jerry Nadler, who is retiring from the 12th Congressional District.

A source close to Conway confirmed that Conway submitted new paperwork with the Federal Election Commission on Monday, indicating his intention to run in the crowded Democratic primary for the district.

“George is a seasoned fighter against Trump and Trumpism, and he’s considering taking that fight to Congress. Today, he filed paperwork that is a prerequisite to run. He will have more to say in the new year after the holidays,” the source said.

Conway later wrote: “I’m going into the arena. I’ve already put my money where my mouth is, but now it’s time to lay it all on the line.”

The 12th Congressional District, one of the bluest in the country, features a field of candidates including former Merrill Lynch managing director Alan Pardee, Kennedy family scion and liberal online commentator Jack Schlossberg, state Assemblymen Micah Lasher and Alex Bores, gun safety activist Cameron Kasky, and journalist Jami Floyd, a former White House fellow in the Clinton administration.

Potential candidates must file with the Federal Election Commission if they meet certain campaign fundraising or organizing benchmarks, though this does not guarantee a formal bid.

Conway’s move follows his recent announcement that he was leaving a podcast to do “either the stupidest thing I’ve ever done or the best thing.”

Conway is the second former Republican and prominent critic of Trump to enter office races. Former Georgia GOP Lt. Gov. Geoff Duncan is running as a Democrat for Georgia governor next year.

The district leans heavily Democratic, making whoever wins the primary next year the heavy favorite to win in November.