Harry Dunn, a U.S. Capitol Police officer who defended the building during the Jan. 6 riot, is joining a wide field seeking the seat being vacated by Democratic Rep. John Sarbanes in Maryland’s 3rd Congressional District.

Dunn, 40, who was awarded the Congressional Gold Medal and Presidential Citizens Medal and published a memoir last year called “Standing my Ground,” announced his candidacy for the Democratic primary on Friday, almost exactly three years after a day that he said took a toll on his emotional health.

“On January 6th, 2021, I did my duty as a police officer and as an American and defended our nation’s Capitol from violent insurrectionists,” Dunn said in a release on Friday. “Today, I’m running for Congress because the forces that spurred that violent attack are still at work and as a patriotic American, it is my duty to defend our democracy.”