There's been a fair amount of excitement in the rightosphere regarding the January 19, 2010 special election to fill the seat of Senator Ted Kennedy. The race pits Massachusetts AG Martha Coakley against Republican state Senator Scott Brown. The cases for GOP optimism are pretty well spelled out in Jim Geraghty's piece at National Review.

There's some truth to these arguments, as Massachusetts isn't as monolithically Democratic as most make it out to be; the real power brokers in the state are the Independents, who make up a near-plurality of the electorate. Hence, Republicans have been able to elect a number of GOP Governors over the last few decades (and in a straight-up match up with Deval Patrick, would probably be poised to do it again in 2010). Jim Ogonowski's near-win in MA-05 in 2007, during the depths of anti-GOP sentiment in the country, gives further proof of the state's willingness to embrace the right kind of Republican (ie a non-Southern, non-conservative Republican without ties to the religious right). In a lot of ways this is the flip of Southern states, which are thoroughly Republican at the Presidential level, but are more politically diverse at the state level.

On the other hand, this is a state that hasn't elected a Republican to the Senate since 1972, when it re-elected Edward Brooke – an extremely liberal Republican (at least by today's standards). And you can tell a lot about this race by what the parties are doing. Or, more specifically, what they aren't doing. I guarantee that with the passage of ObamaCare on the line, the NRSC is polling the state; the fact that we haven't seen any leaked polls or advertisements going up tells you that there isn't much evidence that Brown has much of a chance here. And let's not exaggerate the state's diversity, as there are hardly any Republicans at all in the Massachusetts statehouse.

Nevertheless, in the absence of any polling done in the past month, I embarked on a little thought experiment. One of the interesting things about the 2009 Governor's races was how similar the movements in the states' electorates were. In Virginia, the Republicans' share of the electorate increased by 12% from 2008 to 2009; in New Jersey it was 10%. In Virginia, Democrats were at about 84% of their 2009 level; in New Jersey it was 93%.

In both states, the Democrats' share of the Republican vote dropped by about 50% (50% in Virginia, 56% in New Jersey), and their share of the Independent vote dropped about 66%. The Democrats' share of the Democratic vote was pretty stable; up 1% in Virginia and up 2% in New Jersey.

So what if we see a similar trend going into Massachusetts in 2010? Let me say before I go forward with this that I developed this methodology before I'd looked closely at any of the numbers, and without any real understanding of how the outcome would play out. I was kinda surprised.

I used the CNN exit polls for 2008 – the electorate was 43% Democratic, 17% Republican and 40% Independent. I took the average of the electorate shifts in New Jersey and Virginia, and applied them to the 2008 Presidential election in Massachusetts. If Massachusetts experienced similar shifts, it would have an electorate that's 38% Democratic, 19% Republican, and 42% Independent. This isn't farfetched, as the 2004 electorate was 39% Democratic, 16% Republican, and 44% Independent.

The bigger shift comes in the voting patterns of these groups. In 2008, Obama won 88% of Massachusetts Democrats, 9% of Republicans, and 57% of Independents. If we apply the same methodology here (average of the % swing we saw in New Jersey and Virginia), we come out with an electorate where Coakley wins 90% of Democrats, 4% of Republicans, and 38% of Independents. Again, this isn't terribly off of 2004 for Republicans and Democrats; with swaggering Texan Bush at the top of the ticket, Kerry won 94% of Democrats and 7% of Republicans. The big difference comes among Independents, as Kerry won this group with 54% in 2004.

In any event, if we take a 38%D, 19%R, 42%I electorate and have Coakley win 90% of the Democrats, 4% of Republicans and 38% of Independents, we come out with an exceedingly close 51.06-48.9% Coakley win. I did not expect that.

Now, for three caveats. Obviously, Independents in Massachusetts are probably more liberal than Independents in New Jersey or, certainly, Virginia, so they might swing less. But that's baked into the pie somewhat by using 2008 as the baseline, where they voted more for Obama than NJ and VA Independents did to begin with. And remember, oddly enough, Independents swung more toward Republicans in New Jersey than they did in Virginia.

The other two caveats are more important. Gubernatorial elections are, generally speaking, less partisan than Senate or House elections. They're therefore more prone to partisan swings. Hence, Democrats hold the governorship in Wyoming, while Republicans hold the governorship in Rhode Island. Because of this, the partisan swing since2008 may be less pronounced when a federal race is involved.

Finally, Bob McDonnell, and to a lesser extent Chris Christie, were strong candidates who had something of an established statewide persona. Scott Brown? Not so much. He may be a perfectly capable public servant, but it isn't a great sign that Wikipedia couldn't find a picture of him to put up on their race status entry.

So at the end of the day, you can still place me pretty firmly in the “will be stunned if Brown wins” category. That said, I wouldn't be bowled over if the race was much closer than it should be, perhaps in the 54%-46% range.

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