Yes. Its been very consistent over the past 10-15 years. 85-95% of blacks vote Democrat and turnout stays roughly the same as white turnout. What they can't count on, however, is Latino turnout (usually horrendous in midterm years and OK at best in presidential years), and enough of the white vote for them to win. Not many people on the left recognize it, but they actually do have a problem with white voters. Especially in the Midwest, the white 'working class' people are increasingly Republican.
I generally agree with this, but it remains to see how much of an Obama effect there was on white voters. In 2012, while we did see Obama perform terribly with whites in OH and PA, he performed at 2008 levels with whites in WI and IA, which suggests to me that Democrats are in a decent position there. The 2014 governor elections should also give some hope to Democrats in Western PA, since Wolf did better in Fayette and Greene than almost every county in Eastern PA other than immediate Philly area (DelCo, MontCo, and the city) and Lackawanna. You see a similar thing in Ohio with FitzGerald losing at lower margins along the PA border than he did in the Cleveland suburbs. It'll be interesting to see what effect not having the specter of Obama has on the Midwest.
