What do two former members of Congress (one of whom served time in prison), a former NFL linebacker, and potentially, an embattled former congressman's wife and brother all have in common?

They are all candidates or potential candidates for the seat Illinois Democrat Jesse Jackson Jr. resigned last week, amid a federal probe and health issues. The contest in Illinois's 2nd District is quickly shaping up to be a crowded competition featuring candidates with starkly different resumes. 

Convicted former congressman Mel Reynolds is among the candidates hoping to succeed Jackson. (M. Spencer Green -- AP)

The list of Democratic candidates who have so far committed to running in the heavily Democratic district on Chicago's South Side includes. 

  • Former congresswoman Debbie Halvorson, who lost to Jackson in a primary earlier this year. 
  • Former congressman Mel Reynolds, who resigned in 1995 after being convicted of having sexual relations with an underage worker. Reynolds also went to prison for fraud. He was replaced by Jackson in a special election. 
  • Former NFL linebacker Napoleon Harris, a recently elected state senator who played high school and college football in Illinois. 
  • State Sen. Toi Hutchinson, whose state Senate district covers the majority of the 2nd Congressional District. 
  • Alderman Anthony Beale, who became one of the youngest members to serve in elected capacity on the Chicago City Council in 1999.
  • State Sen. Donne Trotter, who ran against Rep. Bobby Rush (D) and then-state senator Barack Obama in a 2000 congressional race. 

Jackson's wife, Alderman Sandi Jackson, and his brother, Jonathan Jackson, are also possible candidates. 

Gov. Pat Quinn (D) has scheduled the primary for Feb. 26, with the general election to follow on March 19. Because of the district's tilt, the Democratic nominee will be expected to succeed Jackson.

At this point, the race looks wide open. There are several unanswered questions that could tip the race one way or the other. If Jackson's wife or brother were to run, for example, how much would their connection to the embattled former congressman hurt their candidacies?

Another uncertainty is whether Halvorson, who is white, could benefit from a split in the vote among several African-American candidates in the majority black district, a possibility some African-American leaders have already begun to worry about. The 2nd District is home district to President Obama and the 20th century's first black member of Congress.

It all makes for another intriguing special election campaign, which, in the off-year of 2013 will receive a lot of attention.