Conservatives — think in Jonathan Haidt–ish terms here — value tradition, authority, and group identity; liberals value tolerance, fairness, and care. Or whatever; you can draw the distinctions however you'd like. The point is, The Next Generation depicts a strict military hierarchy acting with great moral clarity in the name of civilization, all anti-postmodern, "conservative" stuff — but the values they're so conservatively clear about are ideals like peace and open-mindedness and squishy concern for the perspectives of different cultures. "Liberal" ideals, in other words. You could say, roughly, that the Enterprise crew is conservative as a matter of method and liberal as a matter of goal.TNG has generally gotten a reputation for political correctness, largely because the very prim and proper Captain Picard cuts a very different figure from the green-space-babe-seducing cowboy that was Captain Kirk. Yet this analysis rings true for me. Unlike the later moral ambiguity of Deep Space Nine, the crew of the Enterprise-D were clearly the good guys, and didn't have any reason to be plagued by a guilty conscience.
In many ways, it's a novel solution to our partisan society--achieving liberal goals using conservative methods.
In this reading, Barack Obama is the cautious Picard and Joe Biden is more like the freewheeling Kirk. I'll leave it to the reader to cast Mitt Romney and Paul Ryan.