McCain's Chances Slimmer Than Ever: Silver

John McCain is hanging by a pretty thin thread, writes statistics guru Nate Silver at fivethirtyeight.com, and that thread is Pennsylvania. Two polls show a slight narrowing in Keystone country; one shows Obama’s lead down to 10 points, while another, right-leaning poll puts it at 5. But with no other good news for the Arizona senator yesterday, his overall win percentage probability fell to a new nadir of 2.8%.

New numbers from Colorado and New Mexico are terrible for McCain, there’s still no reason to believe Iowa is competitive, and there’s evidence Obama is on track to win New Hampshire. Polls also give Obama a substantial lead in Ohio and a slim one in North Carolina. Even if Obama lost Pennsylvania, he appears to have enough firewall states to prevail. (More Election 2008 stories.)