Liberals accustomed to chuckling over the ideological rigor of the House GOP caucus won't want to hear this, but one of the foundations of the GOP's broad national success is a reasonable degree of ideological flexibility.
Essentially every state on the map contains overlapping circles of rich people who don't want to pay taxes and business owners who don't want to comply with labor, public health, and environmental regulations. In states like Texas or South Carolina, where this agenda nicely complements a robust social conservatism, the GOP offers that up and wins with it. But in a Maryland or a New Jersey, the party of business manages to throw up candidates who either lack hard-edged socially conservative views or else successfully downplay them as irrelevant in the context of blue-state governance.
Democrats, of course, are conceptually aware of the possibility of nominating unusually conservative candidates to run in unusually conservative states. But there is a fundamental mismatch. No US state is so left-wing as to have created an environment in which business interests are economically or politically irrelevant. Vermont is not North Korea, in other words.
But there are many states in which labor unions are neither large nor powerful and non-labor national progressive donor networks are inherently populated by relatively affluent people who tend to be emotionally driven by progressive commitments on social or environmental issues. This is why an impassioned defense of the legality of late-term abortions could make Wendy Davis a viral sensation, a national media star, and someone capable of activating the kind of donor and volunteer networks needed to mount a statewide campaign. Unfortunately for Democrats, however, this is precisely the wrong issue profile to try to win statewide elections in conservative states.