A very quick thought about Oliver Willis’ observation that African-American turnout will likely be very high in the Democratic Texas primary (also see Amanda and Sonia).
One of the things that did Tom DeLay in was excessive gerrymandering (gerrymandering is where voting districts are shaped in such a way to guarantee victory for a given party). Most of this is done with sophisticated computer simulations, but, like any simulation, they’re only as good as their assumptions.
Many Texas congressional districts were designed to allow Republicans to win ~55-45%. While that maximizes the number of Republican seats, it also made these seats very vulnerable to unusual voting patterns, such as everyone hating Tom DeLay…or unusually high minority turnout.
I’ve said repeatedly that an important criterion for choosing a Democratic nominee should be the effects on downticket candidates. To the extent that Obama gets higher than usual minority (and college student) turnout, this could really screw up some ‘over-gerrymandered’ districts, and perhaps swing a couple House seats to the Democrats.