Updated Obama support graphs

Updating my posts analyzing the correlates of Obama support at the state level, here are some new graphs using the currently available numbers.

In a linear regression predicting Obama's proportion of the two-candidate vote (i.e. his vote plus Hillary's) in contested non-home states (i.e. not FL, MI, AR, NY, or IL), the statistically significant factors are black population (+), Democratic presidential vote (-), having a caucus (+), and levels of state education (+), while Hispanic population, state population (logged), and Southern Baptist population are not, which is largely consistent with my last post. Here are the relevant graphs:

Also, though these factors aren't statistically significant in a linear regression using the same predictors listed above, the white vote for Obama continues to be significantly negatively correlated with a state's black population and Southern Baptist population (the latter has been suggested as a proxy for "Southernness"):

(Notes: In the absence of a clear way to handle the hybrid Texas primary-caucus, I've counted the primary and caucus there as separate observations. The association between black population and Obama vote is concentrated among primary states and the linear fit above is only for those states. White support for Obama is only available in some states due to missing exit poll data. Finally, the fitted line above for Democratic presidential vote excludes the outlier of Washington, DC.)

Update 3/5 9:30 AM: TNR's John Judis has a nice analysis of the exit poll data, as does Jay Cost at Real Clear Politics.

Update 3/6 8:48 AM: By request, here is the graph of Obama support by black population with a quadratic fit, which is heavily influenced by his strong showings in caucuses in heavily-white states (by contrast, the plot above is a linear fit for primaries only):

Comments

[Jinchi]

I was under the impression that the winners of caucus systems generally did better than they would under primary systems. (Look at Romney's outsized wins in Wyoming and Nevada). The caucuses discard lower ranked candidates and reinforce higher ranked ones.

But I don't see that as an inherent advantage for Obama, especially since Clinton has greater support among party leaders and organizers.

In other words, if Clinton had bothered to campaign in Idaho or Alaska or Kansas or Minnesota or Maine she could have been the one to reap the benefits of landslide victories in small states or at least kept Obama's victories to a minimum.

But she and her team have told us repeatedly that those states don't count. She wasn't trying to win them and she isn't going to in the general election either. I think that explains her losses as well as anything else.

[Gray]

Uh, Brendan, pls check your graphs again. Is it really true in all cases that the y-axis represents the "white Obama+Hillary vote"? Because some graphs don't make much sense if they also include Clinton votes, especially the "Obama white support by Southern Baptist population"...
:-/

[Gray]

"But she and her team have told us repeatedly that those states don't count."

Actually, NO, Jinchi. she never said that, and not even her stafers did say that. What Mark Penn did say was thaqt it's important to win the significant states. Ok, of course this leaves the question, what are "significant states"? Well, thinking bad to 2000 and 2004, those are the swing states, and particularly Florida and Ohio. Any nominated Dem candidate needs to win some of them in order to become president. So, nothing real controversial in this remark. all the brouhaha about "some states don't count" is just a fabrication by Obama spinmasters. Always better to check the original quotes before mindlessly spreading such spin.

[Brendan Nyhan]

Gray, only the graph labeled as such represents the white vote (uses data from exit polls). All other y-axes are the overall Obama vote. In both cases, as it says, the dependent variable is Obama's proportion of the total Obama+Hillary vote.