This little math exercise is almost useless as a predictor, since there are so many assumptions. What if Republican support is down? What if moderate Republicans vote Obama? What if Black turn out is through the roof? What if…?

So I offer this up as a look at one possible model of voter turnout, given many, many assumptions:

I’m trying to back into an estimate of what the result of PUMA’s will be for McCain. I spent some time at the PUMA sites, and they believe that there will be about 4 million Hillary supporters voting for McCain, and another 1 million will either sit out or vote 3rd party. This is out of the 18 million that voted for Hillary in the primaries.

So how does that affect the final results on November 4th?

I’m going to make a couple hand-waving assumptions, which are likely to be completely bogus. First, I’m assuming that the basic turn out for 2008 will look a lot like 2004, with a couple modifications. Baseline support, before calculating PUMAs and new voters, will be 39D/39R/26I, just like in 2004. I’m also assuming the baseline overall turnout will look like 2004, before new voters are added in.

In 2004, 121 million votes were cast. Of these, 44.77 million votes were cast by Democrats with 11% of these being cast for Bush. Making another assumption, the 11% crossover in 2004 will be about the same prior to factoring in PUMAs. These people probably represent Democrats who now vote Republican, but never changed registration.

So if we take 5 million votes away, and assign 4 million of these votes to McCain, that is a 9% increase in McCain support, or 20%.

Now the other variable is new voter registrations. Supposedly, 8 million new voters have been added to the rolls. Many of those are ACORN comic book characters, and the odds of them actually voting is probably pretty small. Plus, the 8 million also include natural increase in registration that benefits both parties. So I’ll wave my hands again and assume about 6 million of these people will actually vote, and 4 million of them will vote for Obama.

So let’s take a look at the resultant totals:

Republicans voting McCain – 41.6 million

Republicans voting Obama – 2.7 million

Democrats (non PUMA) voting Obama – 34.8 million

Democrats (non PUMA) voting McCain – 4.9 million

PUMAs voting McCain – 4 million

New voters for McCain – 2 million

New voters for Obama – 4 million

Base support McCain – 52.5 million

Base support for Obama – 41.5 million

This leaves the 31.5 million Independents from 2004 to decide the election. Let’s be honest, in a tough Republican year, they are already leaning toward Obama. But McCain starts out with an 11 million vote lead in base support. Obama would need to get 21.5 million of them to vote for him, or 68% of the Independents, to reach the 50.1% point.

Obviously, this is a wild assed guess, but if the PUMA support really is 4 million, it has a very interesting effect on the race, from a math standpoint.