According to Stephanie Li and Lee Siegel, Romney is the whitest Presidential candidate ever. It sounded vaguely familiar and then I realized I had come across the same bulshytt before in the form of Lenny Bruce's division of everything into “Jewish” and “Goyish.” (I regard it as nonsense because I suspect that Lenny Bruce may have inspired Yasser Arafat. After all, by the Lenny-Bruce standard, Arafat was Jewish and Netanyahu is Goyish.)
This bulshytt is rendered easier by existence of ambiguous groups. If a group can be classified as white or non-white at will, it's possible to have things both ways. If someone who is Jewish/Chinese/Irish/whoever disagrees with the Enlightened Ones, that can be attributed to being white. When similar people agree with the Enlightened Ones, they have the absolute moral authority that comes from being underprivileged or, at least, having at least one underprivileged great great grandparent.
Meanwhile, to the extent the claim that Romney is particularly white makes any sense whatsoever, it comes from the fact that he came from a background of hereditary privilege. By that standard, of course, the whitest President was FDR.