Obama has been doing well among registered Democrats, but he has been doing even better among independents and the few Republicans who are voting in the Democratic primary contests. His performance outside his own party bodes well for the general election if he were to become the nominee.
The CNN exit polls for Wisconsin reveal that an amazing 37% of voters were not registered Democrats (or at least not self-described registered Democrats). So what does that high independent turnout suggest for Ohio? An analysis follows based on the latest polling.
SurveyUSA's latest Ohio poll suggests that Clinton is running 9 points ahead of Obama in that all-important "firewall" state. Like Wisconsin, Ohio is also an open primary, meaning that independents and Republicans are eligible to vote, although they may have to switch registration at least temporarily to do so.
Looking at the poll's internals, SurveyUSA projects a 17% turnout among independents and Republicans. That figure is not just low in comparison to Wisconsin, it is also low compared to the exit poll results from several earlier states. Earlier states also still had an active Republican contest competing for voter attention. So I think SurveyUSA is undersampling independents and Republicans.
Again, according to CNN in Wisconsin, independents and Republicans are breaking for Obama 2 to 1 over Clinton. The math here is quite simple then. If the Ohio electorate is actually 20% independent/Republican instead of 17%, Obama would pull one point from Clinton, resulting in a 7 point Clinton advantage.
Now, I am not expecting a 37% independent/Republican turnout in the Ohio Democratic primary. That would be an amazing number, even if we just saw it. But let's suppose the number is actually 26%, not 17%. For comparison, in Missouri 28% of the voters were independent or Republican, so 26% does not seem unreasonable for a state like Ohio. Missouri and Ohio have similar demographics and similar presidential voting patterns. And let's suppose SurveyUSA's poll is completely accurate in reflecting the current state of the race in Ohio. SurveyUSA has been one of the most accurate pollsters this cycle. If all these assumptions hold, that would mean Obama would pull 3 points from Clinton, resulting in a swing of 6 points and a mere 3 point lead for Clinton in the overall result.
Of course this analysis is speculative, but if Obama can continue to attract 2 to 1 support among non-Democrats while continuing to improve his standing among registered Democrats, and if those non-Democrats turn out to vote, Ohio could already be a lot closer than people think.
Update: See "For You Math Junkies..." below for a more precise estimate. It's actually a 4% Clinton lead, not 3%, if all the above assumptions hold.