For a look at the 2012-2020 electoral college map based on the 2010 Census click here. And for look at how those changes would have affected the 2008 presidential election click here.
On Monday, Election Data Services released the US population estimates for 2008 and a series of projections for 2010. So let's have a look at how the electoral college map would change given the new information we have.
The first set of numbers we have is the estimate of the population changes during 2008. This is more of an "if the Census was done today" scenario. It was this set (from 2007) that we used to project the the map for 2010 before. In other words, this gives us an idea of what the changes might be for 2010, but not the full picture. EDS even said in its report that they expected quite a bit of volatility over the next two years despite the economic downturn's impact on mobility.
[You'll notice that the map has taken on the red and black color scheme that denotes gains and losses in the financial world. Red states are states losing seats while black states are those likely to gain seats following the 2010 Census.]
Despite that, we can set a baseline of potential changes based on the changes from 2008 (Well, from 2000-2008). The picture here isn't that much different from what we witnessed a little more than a month ago. Basically, Texas would gain an additional seat, Missouri wouldn't lose the seat it was projected to have lost and Michigan and New Jersey would lose a seat apiece. That would have fueled an additional two electoral vote swing toward John McCain in November's electoral college. Taken with the information we had before, though, that still would have put the Arizona senator at a 360-178 electoral vote disadvantage. Still, we're talking about a population shift toward redder states. Of course the traditional question is, "Who are those people?" Are they more Democratic or Republican? Are these states becoming redder, like, say, Georgia, or purple like Virginia (though the latter is not a state projected to gain or lose any congressional seats)?
But let's move from an estimate of the map based on the population changes we have seen during 2008 and focus on the projected changes we could see in 2010 based on likely changes over the next two years. Now, EDS set up several different models: one that projected population shifts based on what has happened since 2000, and four additional models that took a midterm approach; focusing on population shifts from 2004 onward, 2005 onward, 2006 onward and 2007-2008. For our purposes, we'll take the model with the most information: the full model based on the changes since the last Census.
That version shows Arizona (2 seats total), Florida (2) and Texas (4) gaining additional seats on top of the gains shown in the map above. It also has South Carolina picking up a seat.
On the opposite side of the ledger, Ohio is likely to lose a second seat, while Missouri once again loses the seat it lost on the initial version of this map. Illinois and Minnesota round out the remaining list of states either losing population or not growing at rates fast enough to stay apace of the states gaining seats. If this projected map had been used in the November election that would have netted McCain an additional two electoral votes from the first map above. In other words, playing on the map immediately above, the 2008 election would have come to a count of 358-180 in favor of Obama. Again, this isn't a big shift in an election like we just witnessed. In a more competitive election, however, such a shift could prove consequential. Recall that the generic ballot question favored the Democrats throughout the 2008 cycle. If that divide had been more even, a seven electoral vote swing could have been decisive.
So what does all this mean? Well, not much. Projections are nice, but they aren't the real thing. I really ought to look back at how well these EDS projections were prior to the last Census. That might be a factor to throw into a more inclusive model -- similar to the house effect that FiveThirtyEight factored into their electoral college projections late in the game in 2008. With EDS cautioning that there could be volatility in the forecasting over the next two years, you have to take these numbers with a grain of salt. However, it is interesting to note what the map might look like in four years' time.
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