Silver's projection has become more favorable for Obama:
If the national popular vote winds up roughly tied, instead of favoring Mr. Obama by two points or so, then Mr. Romney could claw back to win Florida, Colorado and Virginia, and perhaps Iowa and New Hampshire. But Mr. Obama’s lead in Ohio, Wisconsin, Nevada and Pennsylvania is clear enough to withstand some underperformance in the polls, and his margins in the polling averages there have converted into a victory on election night a very high percentage of the time historically.
In order for Mr. Romney to win the Electoral College, a large number of polls, across these states and others, would have to be in error, perhaps because they overestimated Democratic turnout. It’s this possibility, more than the chance of a successful hail-mary in a state like Pennsylvania, that accounts for most of Mr. Romney’s remaining chances of winning the Electoral College.