[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/03/03/art.getty.rahm.emanuel.jpg caption="t's a crowded ballot today in Chicago, where nearly two dozen candidates are running in a special primary election to replace former Rep. Rahm Emanuel."](CNN) - It's a crowded ballot today in Chicago, where nearly two dozen candidates are running in a special primary election to replace former Rep. Rahm Emanuel.
Twelve Democrats, six Republicans and five Green Party candidates are vying to succeed Emanuel, who was re-elected in November to a fourth term but stepped down at the beginning of this year to serve as President Obama's White House Chief of Staff.
The winners of each party's primary will face off in a general election contest on April 7.
The district stretches from Chicago's wealthy North Side along Lake Michigan to more middle class ethnic enclaves in the northwest part of the city to suburban areas in neighboring Cook County. The district is dominated by Democrats. Emanuel won 78 percent of the vote in his re-election last November.
"This is a solidly Democratic district. It went overwhelmingly for Barack Obama. A Democrat has make an effort to lose that seat," says CNN Senior Political Analyst Bill Schneider.
Chicago residents have been bombarded with campaign commercials: Through Saturday, 742 TV ads had run, at a cost of nearly $1.4 million.
"It's 'healthy' spending for a special election, driven by no clear cut candidate from the Democratic party for the seat and the prestige of winning the new White House Chief of Staff's old congressional seat," says Evan Tracey of TNS Media Intelligence/CMAG, a leading provider of advertising tracking. "This comes at a price. This race has a full field and spending by unions."
Emanuel is the not only well-known politician to serve as congressman from Illinois' Fifth District. The seat was also once held by Rod Blagojevich, who earlier this year was impeached and removed as Illinois governor. It was also held for nearly four decades by former Rep. Dan Rostenkowski, who was later convicted and imprisoned on federal corruption charges.
The Democrats currently hold a 254 to 178 majority in the House of Representatives, with three seats vacant.