Nate Silver, the number-cruncher at FiveThirtyEight.com, has been an indispensible voice in this election. So pay attention when he says that McCain’s coming wave of negative attacks probably won’t work. The problem: McCain can’t “make this election about Obama,” as his supporters hope. The election is also about McCain—his integrity and distance from the GOP brand. With every negative attack, McCain’s own negative numbers tick up—Silver provides a handy chart. Obama's dilemma, meanwhile, is how and how much to respond. Today, he fires off a lengthy film exploring McCain's ties to the Keating Five and that scandal's parallels to today's economic crisis.