New Orleans Councilmember-At-Large Jason Williams drills Orleans Parish District Attorney Leon A. Cannizzaro, Jr., about the use of fake subpoenas and the jailing of witness that had not committed a crime during a budget hearing for the DA's office in City Council Cambers at City Hall in New Orleans, La. Wednesday, Sept. 20, 2017.

City Council President Jason Williams told a packed New Orleans Film Festival audience Tuesday night that he’s in the 2020 race for Orleans Parish district attorney.

Williams, 45, made plain what many political observers had long expected: that he’ll take another run at a position he sought a decade ago, when he ran a distant third to Leon Cannizzaro.

Williams made his surprise announcement in response to a question at the end of a panel discussion following a screening of a documentary on the Orleans Parish criminal justice system titled “Guilty Until Proven Guilty.”

Williams, a criminal defense attorney who is in his second term on the City Council, features prominently in the film in his familiar role as one of Cannizzaro’s leading critics.

The documentary traces the course of one armed-robbery suspect’s troubled route through the court system, while casting a critical eye on Cannizzaro for, among other things, his prolific use of the state’s habitual-offender law to ratchet up sentences for repeat offenders.

During a panel discussion afterward, an audience member asked Williams about running for DA again, to which he responded, “2020.” Afterward, another audience member asked Williams if he was serious.

“Absolutely,” he said. “I’m on it.”

Reached later, Williams acknowledged he was throwing his hat in the ring.

“I think we need real change. It’s costing us money, and it's costing us lives, and I’m committed to bringing that reform,” he said.

Williams is the first candidate to announce for the district attorney’s race, still roughly two years away.

It should make for an interesting situation when Cannizzaro goes before the City Council next month to explain and defend his budget allocation for 2019, and perhaps to ask for more than Mayor LaToya Cantrell is prepared to recommend.

Follow John Simerman on Twitter, @johnsimerman.