Taylor Swift is that rarest of pop phenomena: a superstar who managed to completely cross over from country to the mainstream. Other singers performed similar moves -- notably, Dolly Parton and Willie Nelson both became enduring mainstream icons based on their '70s work -- but Swift shed her country roots like they were a second skin; it was a necessary molting to reveal she was perhaps the sharpest, savviest populist singer/songwriter of her generation, one who could harness the Zeitgeist and turn it personal and, just as impressively, perform the reverse. These skills were e...