Eye on 2010

Jackson has headed the Chicago Urban League since October 2006 and previously served as communications director for Democratic Gov. Rod R. Blagojevich, who was removed from office this January in part because of an allegation that he tried to auction off the Senate seat.

Jackson is seeking to become the second black woman ever to serve in the U.S. Senate, following another Illinois Democrat, Carol Moseley Braun, who held the same Senate seat from 1993 to 1999.

Jackson's name surfaced last fall as a potential successor to Obama. After his election but before his inauguration, Obama had included Jackson among a handful of potential Senate appointees he thought were qualified to hold the seat.

State Treasurer Alexi Giannoulias formed an exploratory committee in early March and is a likely candidate for the Democratic nomination. Also weighing a campaign is Chris Kennedy, a son of the late New York Sen. Robert F. Kennedy who is president of Chicago's Merchandise Mart.

Burris hasn't said whether he will seek a full six-year term, but he has done little fundraising and has incurred substantial legal bills as a result of investigations into the truthfulness of his testimony in January before an Illinois legislative committee that recommended Blagojevich's impeachment. An Illinois prosecutor said earlier this month that there was insufficient evidence to charge Burris with perjury.

It's also not clear whether state Attorney General Lisa Madigan will run for the Senate. She's also weighing a campaign for governor.

Rep. Mark Steven Kirk is weighing a campaign for the Republican nomination.

The Democratic and Republican primary elections will be held next Feb. 2.