The Illinois governor on Sunday set April 9 as the general election date for the open seat of former Democratic Rep. Jesse Jackson Jr.

Jackson resigned last month citing debilitating mental-health issues and under the cloud of a federal investigation.

Gov. Pat Quinn, a Democrat, said he wanted the special election to be April 9 to coincide with already scheduled municipal elections, in part as a cost-saving measure. However, he needed approval from the Democrat-controlled General Assembly.

Quinn has already scheduled Feb. 26 as the date for the primary election, which will likely decide the eventual winner, considering the state’s 2nd congressional district includes Chicago’s South Side and is heavily Democratic.

A wide open field of potential Democratic candidates has already emerged including prominent Chicago attorney Sam Adam Jr., Chicago Aldermen Sandi Jackson and Anthony Beale, Cook County Board President Toni Preckwinkle, and former Rep. Debbie Halvorson, who lost to Jackson in this year's primary.

Jackson's health issues became public after he left Capitol Hill unannounced in June, then news trickled out weeks later he was seeking treatment for bipolar disorder, including treatment at the Mayo Clinic in Rochester, Minn.

The House Ethics Committee had already been investigating the 10-term congressman for his political dealings with imprisoned ex-Illinois Gov. Rod Blagojevich. And more recently, Jackson became the focus of a federal probe on the possible misuse of campaign funds, reportedly to decorate his Washington home.

The 47-year-old Jackson, son of civil rights leader Jesse Jackson, acknowledged his health and legal problems in his Nov. 21 resignation letter.

"As my health has deteriorated, my ability to serve the constituents of my district has continued to diminish,” he wrote. “I am aware of the ongoing federal investigation into my activities and I am doing my best to address the situation responsibly.”