Michael Tomasky: "I've been pounding away at Mitt Romney's lack of spine on the basis of his unprecedented reversals of position. We have never in modern American history had a presidential nominee who, as he ascended from the state to the national level, changed so many positions so shamelessly. But that's not the only manifestation of his weakness. Take the three issues of his lack of specificity about the policies he supports, his inaccessibility to the press, and his refusal to release his tax returns. These highlight another aspect of the problem, one that's no less telling and serious: His desire to sneak into the White House all but unexamined by voters."