With a new House at work in DC, Democrats are now back up to their pre-1994 election numbers, and we can make a direct comparison of the composition of the parties. For this year, below, I show a distribution of the seats held by each party according to how their district voted in 2000, with a smooth curve drawn through the data:
Below, you'll find the comparisons going back to 1994 as well as some info on where the representatives come from. Here's a preview:
The quick take is that Democrats now represent more liberal districts than they did just before the 1994 midterms, and Republicans represent more conservative districts. In other words, Obama has a much better chance for a cooperative Democratic caucus in the House than Clinton did. In addition, almost half of Republicans are now from the South. Previously, this was not the case.
Change in the House
Let's simplify the graphs above to just the smooth curves for both parties:
We can see the Republicans are having a devil of a time getting elected in districts that did not vote for Bush in 2000. With the glaring exception, of course, of a certain district in Louisiana - that's that little red bump way out to the left. The House has shifted leftward compared to 2000 presidential results: Of those districts that voted between 46-50% for Bush in 2000, Democrats now hold 77%. But of those districts that voted 51-55% for Bush, Republicans only hold 55%.
Let's look back in time. On the left, the curves shown above are plotted along with the curves from just before the 1994 midterm elections. On the right, an animation for the whole time period.
In 1993, we had Democrats representing districts across the spectrum of politics, and Republicans representing districts across most of the spectrum (but not the most liberal). Now, we have achieved a fair amount of separation between the two parties - political chromatography, so to speak. After the 1994 election, this separation began to take place, with Democrats and Republicans swapping liberal for conservative districts. Then, in 2006 and 2008, Democrats pushed over the 50% line and into Republican territory (note there's still room to grow...). Democrats, although still elected from conservative districts, are rare in districts that voted for Bush by 61% or more in 2000 (7 now, 18 in 1993), while Republicans are rare in districts that voted for Bush by 45% or less (4 now, 30 in 1993). Here's a graph that makes this more clear:
There's simply a much sharper distinction between the parties now.
Warts and Things
There's several flaws associated with these graphs. First, it is convenient to use Bush 2000 vote totals to categorize districts because it splits the country in half, and we have numbers for pre-2002 districts and post-2002 districts. But, because presidential campaigns ignore many states, the votes can be exaggerated. Also, we have home state effects in Texas and Massachusetts. Another thing is that the conservative/liberal dichotomy does not line up perfectly with Bush/Gore (although exit polls show 80% of conservatives voted for Bush and 80% of liberals voted for Gore). Finally, districts change over time, and not all districts change in the same way at the same rate.
We can chop things up in several other ways to look at this in more detail. First, race: Republicans have a damn hard time getting elected in any district that's less than 60% non-Hispanic white. This hasn't changed much in the past 20 years, although there is some change. Republicans have gone from representing 16% of majority-minority districts to 9%, as the number of majority-minority districts increased. For districts less than 60% non-Hispanic white, they've gone from 20% to 13%.
We can be more specific, though, and look at the numbers by race and region:
Democrats lost white Southern districts to Republicans since 1993. So very surprising, huh?
Let's look at a more detailed regional picture:
Essentially, Democrats lost Texas, but gained all of New England and a fair chunk of the Mid-Atlantic. What is striking is that both parties used to have proportionate representation throughout almost all regions - 55% to 67% Democratic everywhere except the Mountain states - but now there is a wide divergence, from 28% in West South Central to 100% in New England.
I don't like the census groupings of states - it doesn't make sense politically - so I also used Robert Sullivan's ten regions, which do not follow state boundaries, to divide up the country. Being a crank, I take issue with these too, but what the hey. Here they are:
In addition to the Texas/Northeast trade-off, we learn a little more from this set of definitions: the cities of the Southwest (El Norte) trended towards Democrats, while the remaining portions of the Interior West (Sagebrush) and Appalachia moved towards Republicans. Not earth-shattering news, of course. Sullivan also updated his map after the 2006 elections; I like the newer version less, but here's the matching graph for it.
Looking Back, Looking Forward
Overall, Democrats are now a national, yet more liberal, party as defined by their House districts, while Republicans have been reduced to a mainly white, Southern party. There is a much clearer separation between the two parties in the House now than when Clinton first came into office. Is this the natural final result of a decades-long realignment or a temporary problem resulting from recent hyperpartisan rhetoric?
Cross posted at Open Left.