Cook County Chief Administrative Officer Robin Kelly won the Democratic nomination in the special election to replace former Rep. Jesse L. Jackson Jr. on Tuesday and is now poised to succeed him in Congress.

Kelly had 55 percent, former Rep. Debbie Halvorson had 21 percent and Alderman Anthony Beale had 11 percent, with 63 percent of precincts reporting, according to The Associated Press.

Kelly’s win also marks a victory for New York City Michael Bloomberg, whose super PAC spent more than $2 million in the race. Bloomberg supports gun control, which became a central issue in the race for the district on Chicago’s south side. The area has endured a spike in gun violence in the past few years.

This was Bloomberg’s first foray into congressional races since the elementary school shootings in Newtown, Conn., last year. He spent millions of dollars knocking Halvorson, who received support from the National Rifle Association in her previous races, and boosting Kelly.

Another Democrat who suffered from Bloomberg’s barrage, state Sen. Toi Hutchinson, dropped out of the race a couple of weeks ago. But it was too late for Hutchinson to withdraw from the ballot, so she still picked up 2 percent of the vote.

The special general election is April 9. But the heavy Democratic lean of the district means Kelly will be its next member in all likelihood.

Jackson resigned from Congress last year. Early this month, he pleaded guilty to improperly spending campaign funds on personal purchases.