CHICAGO — Embattled Sen. Roland Burris may have relieved Illinois Democrats of their biggest political headache and reduced Republican chances of capturing a valuable Senate seat next year by announcing Friday he won't run for a full term. Still, his withdrawal sets the stage for a major clash of political forces in 2010.

Democrats no longer have to worry about a messy primary battle focused on Burris accepting his seat from former Gov. Rod Blagojevich, now removed from office and facing multiple corruption charges. And Republicans won't have a chance to run against the tainted appointee.

Even so, Republicans who run are sure to campaign against the scandals surrounding Blagojevich in this Democrat-controlled state. Democrats must sort through a wide-open field that could include anyone from a protege and basketball pal of President Barack Obama to a son of the late Robert F. Kennedy.

Black leaders also may fight hard to hang on to a seat held in recent years by three black senators: Burris, President Barack Obama and Carol Moseley Braun. Burris is currently the Senate's only black member.

Burris' announcement that he was dropping out came just seven months after he was named Obama's replacement. It was an admission that Burris' image had taken such a pounding from his association with Blagojevich and that it would take too much campaign money and time to turn things around, if it could be done at all.

"I was called to choose between spending my time raising funds, or spending my time raising issues for my state. I believe that the business of the people of the state of Illinois should always come first," said Burris, 71.

Burris, who bemoaned the high cost of running a political campaign, has had lackluster fundraising, raising only $845 during the first three months of 2009. He delivered the news that he was bowing out in a brief speech at a South Side hotel to a crowd of about 50 supporters, who applauded and chanted "Don't Do it" and "Run, Roland, Run!"

"I feel as if the people of Illinois have lost the most experienced and most qualified person to represent them in the United States Senate based on finances, based on a simple matter of campaign fundraising," said Melvin Sims, a Chicago attorney.

Burris greeted supporters after his speech but left without taking questions, which has been typical during his tenure in office.

His decision is the second major development in the closely watched Senate race this week. Illinois Attorney General Lisa Madigan, who would have been a likely leader in the Democratic primary, opted out of the race on Wednesday.

But with Madigan and Burris out, the field is full of potential front-runners.