Demographic changes might eventually break the Republican siege of those poor liberals in Austin. But for now, there isn’t a pathway to victory for progressive Texas Democrats. Obama lost by 16 points last November, despite favorable turnout and demographic trends. It’s even tougher for Democrats in an off-year, when non-white and young voters are unusually likely to stay home. In 2014, the white share of the electorate might increase to about 62 percent, up from 58 percent in 2012. …

It is difficult to overstate how hard it will be for Davis to assemble the requisite number of white voters. Last November, Obama might not have even received 20 percent of the Texas white vote. To win, Davis will probably need to approach the mid-thirties.

It’s just not realistic to expect such massive gains. More than half of Texas white voters were evangelical Christians in 2010. Those voters broke for Perry by a massive 84-15 margin, and even more for Romney. It’s inconceivable that Wendy Davis, a liberal heart-throb best known for filibustering an anti-abortion bill, would make outsized inroads among southern Evangelical Christians. She could easily do worse.