Several things are worth noting here. The first is that, in today’s Republican politics, one reliable way to reach beyond the Christian base is by whipping up nationalistic hysteria with language lifted straight from the McCarthy era. If criminalizing all abortions and nullifying all gay marriages are a little too sectarian for you, surely you’d like to try some old-fashioned traitor-hunting. (Santorum has also accused Obama of “sid[ing] with evil” in Iran, a country with which he plainly wants to go to war.)
The second is that this kind of gutter rhetoric is so routine in the Republican campaign that it’s not worth a political journalist’s time to point it out. In 2008, when Michele Bachmann suggested that Barack Obama and an unknown number of her colleagues in Congress were anti-American, there was a flurry of criticism; three years later, when a surging Presidential candidate states it flatly about a sitting President, there’s no response at all. Certain forms of deterioration—like writers using “impact” as a verb, or basketball coaches screaming about every foul—become acceptable by attrition, because critics lose the energy to call them out. Eventually, people even stop remembering that they’re wrong.