Chicago voters are poised to decide who takes over the congressional seat previously held by Jesse Jackson Jr., who resigned in November and has since.
The winner of today's Democratic primary in the heavily Democratic second district is widely expected to triumph in the April 9 special election.
There are 14 Democrats in the race - along with four Republicans - but three real Democratic frontrunners: Former U.S. Rep. Debbie Halvorson, Alderman Anthony Beale and former state Rep. Robin Kelly. One recent poll by Victory Research for WCKG-AM Radio showed Halvorson with a slight lead, holding 21 percent of the vote to Kelly's 17 percent.
The race has become something of a proxy battle between New York Mayor Michael Bloomberg and the National Rifle Association. Bloomberg's Independence USA PAC, saying her "record on gun safety has been entirely devoid of any semblance of the kind of common-sense reforms that will keep Americans safer from the scourge of gun violence."
Chicago has been hard hit by gun violence, something President Obamain which he noted that 443 people were killed with firearms in Chicago last year.
Rep. Bobby Rush, D-Ill., joined Bloomberg in endorsing Kelly in the race, saying she "supports common sense gun control measures such as a comprehensive ban on assault weapons, the elimination of gun show loopholes and a ban on high capacity ammunition magazines."
Beale, meanwhile, has worked to shift the focus of the race to jobs.
While campaigning last weekend, Halvorson railed against Bloomberg for trying to influence the race, CBS Chicago reported.
"The first thing out of their mouths is, we're sick of those commercials," she said of voters, adding that they are telling her: "We're voting for you, we don't want the mayor of New York coming in and trying to buy a seat in Congress."
Kelly has denied allegations that she has ties to Bloomberg's PAC, calling the accusations "ridiculous."