There are two major reasons for Mark Kirk's flip-flopping on the Illinois Senate race: the national energy tax and Illinois Republican Party Chairman Andy McKenna's decision to run anyway. Kirk apparently hoped the party would clear the field for him. Instead Republicans were steamed by his vote for cap and trade. Kirk supposedly rethought his candidacy after Republican members of the Illinois delegation said they might not support him over McKenna due to the national energy tax. Now we'll see if national GOP bigwigs can muscle McKenna out of the race to bring back Kirk.