Mark Kirk's campaign put out a poll yesterday claiming to start the general election with a 12 point lead over Alexi Giannoulias, which was a little surprising to me since we found Alexi up by eight points just two weeks ago. I'll give Kirk points for transparency though- he put the full results from the poll online.
Of course doing so makes it clear how the big lead in the poll was possible. Just 49% of those surveyed report voting for Barack Obama in 2008 to 42% who say they voted for John McCain. Obama won the state 62-37.
It is more than likely that the folks who turn out this fall will be less Obama friendly than the folks who turned out in 2008, but not to that extent. Our final Massachusetts Senate poll found the electorate there had supported Obama by a 56-37 margin, just a 7 point drop on the margin from his 62-36 victory there. Use a 59-41 Obama split on the Kirk poll and you get a 44-39 lead for Kirk, relatively similar to this morning's Rasmussen poll.
Beyond that it's important to note that more than 2/3rds of the undecideds in the Kirk poll were Obama voters- distribute those proportionally and you have a 50/50 race, which feels about right at this point. The last couple of weeks of the primary were a lot harder on Giannoulias than they were on Kirk, and his fate may be determined by the extent to which he is able to unify Democratic voters around him now that he's the guy.