I think, the point is that in a Christian society, one either recognizes that God is the fount of truth, and truth must be assiduously pursued--even to the point of swearing to one's own hurt--or men are without a reference point for truth. Professing Atheists were once banned from various offices, were once regarded as unreliable witnesses (thus couldn't be called to the stand in court)--why? because it was generally conceded that ones-self as an ultimate authority was prejudicial to the truth.
This is not the same thing as denying that atheists tell the truth, or that they are incapable of telling truth from falsehood, etc. No one is saying that this Islamist going to Washington is incapable of being truthful, or of being a good secularist, who divorces his faith from his business.
Catholics (once a minority) were once regarded by the American electorate as having questionable loyalties, given their devotion to the pope. This type proved they were not devoted to the pope, but rather to power, thus proving themselves capable of selling out everybody just as easily as any apostate Protestant.
This Muslim's declared faith is, however, inimical to abolute truth. His god openly declares himself to be a liar when it suits him. And so, when push comes to shove where will this guy land? Who knows? That's the point.
And right, in the final analysis that won't make him any different from any of the other practical atheists and those who worship power, who have insinuated themselves into the thrones of authority. I just think it's worth noting that his declared beliefs prejudice him to the truth. So when the chickens come home to roost, there were those on record who will say--"Y'all got what you deserved. Covenantally, we all did."
