ABC News’ Rick Klein reports: The 2010 primary season kicks off tomorrow in Illinois. What better way to test the perils of incumbency, and the Obama coattails, than in President Obama’s home state? As both parties choose candidates for the president’s old Senate seat, and for the scandal-tarred governor’s office, some observers are predicting that Illinois could be the new Massachusetts — just two weeks after a Republican stunned the political world by grabbing a Senate seat in that bluest of blue states. “What you have here in Illinois is a very weakened Democratic Party,” Rick Pearson, a veteran political reporter for the Chicago Tribune, told us from Chicago on ABC’s “Top Line” today. “This state has basically been a Democratic-ruled state for the last eight years. And what I think you’re going to see is the stage being set through these primary elections tomorrow [for] obviously a very closely watched national race for Barack Obama’s own seat.” As for the prospect of Democrats losing Obama’s own seat, with Republicans appearing likely to nominate Rep. Mark Kirk, R-Ill., Pearson said: “There’s no doubt that the White House is very concerned.” Watch the segment of today’s “Top Line” with Rick Pearson HERE.