Updated

Rep. Mark Kirk is sounding increasingly confident about his run for President Obama's former Senate seat, as he looks to become the latest Republican to pose a serious challenge in traditionally Democratic territory.

Kirk, a social moderate who's recast himself as a fiscal conservative, has been largely unchallenged in the GOP primary set for Feb. 2 and is now viewed as a threat by Democrats.

Even Obama has been asking questions about the race.

"Naturally I won't share the details, but he is following this race closely and talking about November," said Illinois Democratic Sen. Dick Durbin.

Illinois is true-blue territory, but Kirk isn't exactly vying for the seat under normal circumstances.

The seat Obama left is the one former Democratic Illinois Gov. Rod Blagojevich allegedly tried to sell to several politicians and then gave to Democrat Roland Burris -- who has had to answer ethical questions of his own since taking the seat.

On top of that, Democrats nationwide appear to be facing a backlash from voters, witnessed most recently in the Massachusetts special election, in which Republican Scott Brown beat Democrat Martha Coakley for the seat formerly held by the late Sen. Ted Kennedy.

"We're seeing a collapse of support for the organized Democratic Party ... in places that we never thought would happen," Kirk said, citing the Massachusetts election. "I think that will happen in Illinois as well."

Democrats surely don't want to see a Bay State election repeat.

Though the national party faced some criticism in Massachusetts for not coming to Coakley's aid early enough, White House Senior Adviser David Axelrod said the White House will be "fully supportive" of the Democratic nominee in the Illinois race.

But with polls suggesting one-in-four likely Democratic primary voters is still undecided, that contest is still up in the air, with a week to go.

The leading Democratic candidate is 33-year-old state Treasurer Alexi Giannoulias, a friend and occasional basketball-playing guest of the president.

Giannoulias has high name recognition in Illinois and is a very good fundraiser but still faces nagging questions about his old job in the family business - Chicago's Broadway Bank, which is losing money fast. It was $27 million in the red through the first nine months of 2009.

But while Broadway was slipping, it paid $86 million to shareholders, including Giannoulias and his family.

Other Democrats to watch include Cheryle Jackson, Chicago's Urban League president. Polls have her in second place going into the primary.

The biggest mover in the polls in the last six weeks is Chicago's Inspector General David Hoffman. A flurry of glowing newspaper endorsements, including one from the Chicago Tribune and one from the Chicago Sun-Times, have boosted Hoffman in the last few weeks.

"I have to say the endorsements really helped," Hoffman said.

Fox News' Steve Brown contributed to this report.