WASHINGTON -- The White House had been working for months to talk Illinois Attorney General Lisa Madigan into running for President Obama's former Senate seat to keep it from falling into Republican hands.

Madigan is popular, has high voter-approval poll results, and was seen as the strongest Democrat who could hold the seat. But in an unexpected blow to the White House's political recruiting efforts, she turned down the president's request and decided to run instead for re-election to her present job.

Within hours of her decision Wednesday, Republican Rep. Mark Kirk saw his chance and sent out word that he was running for the seat now held by Democratic Sen. Roland Burris, who recently announced he will not seek election to a full term. Appointed to fill Obama's seat by disgraced Gov. Rod Blagojevich, Burris has been the target of a Senate ethics committee inquiry into whether he offered any quid pro quo in exchange for his appointment. This all happened before Blagojevich was impeached and removed from his office on charges that he sought to sell the seat to the highest bidder.

Until now, no one thought the Republicans had a chance to win the Senate seat in heavily Democratic Illinois, especially in the present climate when the GOP's brand has been badly damaged. But Kirk may be the one candidate who can pull it off in a state where widespread state corruption has badly damaged the Democrats' brand even more.

The youthful five-term congressman represents the Democratic-leaning 10th congressional district that Obama carried last year by 61 percent, but Kirk's cross-party appeal has kept it in the GOP column against all comers.

He is a prodigious fundraiser, too, raising more than $580,000 in the second quarter, amassing a total of $1.1 million.

"Kirk is a very strong statewide candidate for Republicans. This is an easier race for them now that Madigan is not running," said Jennifer Duffy, senior elections analyst at the Cook Political Report.

But other Democrats were expected to run for the seat next year no matter what Burris decided, promising a potentially divisive party primary fight that could further weaken their party's chances of holding on to the seat. State Treasurer Alexi Giannoulias has already announced that he is running, and businessman Chris Kennedy was also expected to enter the race.

Madigan's decision to forgo the Senate contest was not only a major disappointment to the White House but a personal blow to White House's chief of staff, Rahm Emanuel, a former congressman from Chicago who has also become Obama's chief candidate recruiter.

Madigan, a top Democratic vote-getter in the state, was called to the White House last month where she met with Obama, Emanuel and senior adviser Valerie Jarrett in what insiders say was a full-court press to draft her for the race.

This has not been an especially good month for Obama and his White House team to demonstrate their political firepower. So far they have failed to get their way in three key battleground Senate races.

New York Rep. Carolyn Maloney ignored their political pleas against challenging Sen. Kirsten Gillibrand for the party's nomination in next year's contest to fill Hillary Clinton's seat. None other than former President Bill Clinton is headlining a gala fundraiser for Maloney on July 20, despite the White House's heavy efforts to consolidate the party establishment behind Gillibrand.

Then Pennsylvania Rep. Joe Sestak dissed the White House efforts to keep him from running against Sen. Arlen Specter, the recent Democratic convert whom Obama and Gov. Ed Rendell have embraced.

And now Madigan has flatly turned down Obama's request to take his old Senate seat.

Meantime, while the Illinois Senate race has suddenly become a more competitive contest with Madigan out and Kirk in, a number of questions "need to be answered" before its direction becomes clear, Duffy told me.

"Does Kirk get a competitive primary? Can Democrats avoid a bruising primary?" she said.

"One thing to remember is that Illinois has a very early filing deadline, the first week in November, and an early primary in March. This means that Democrats might be less concerned with the fallout from a primary, and more with making sure that a viable general-election candidate emerges from that contest," she added.

But as things stand now, Kirk's candidacy may in the end benefit from what is turning into a perfect Democratic storm that has badly damaged their state party's credibility. Blagojevich has been impeached and is facing a corruption trial. His former chief of staff has pleaded guilty to having a hand in the scheme to sell Obama's Senate seat. Burris has been an embarrassment to the state.

Sounds like Illinois Republicans may be borrowing one of Obama's old campaign lines next year: "It's time for a change."