This is a representation of the last Cook Political Report snapshot (May 10, 2012) of the race. Toss-up states are CO, IA, NV, OH, PA, & VA (note that NC & NH are conceded to the GOP). Now, obviously some of those states will go to the Democrats… but not all of them. And there aren’t that many combinations to make the numbers come out right. Here’s the best firewall that I could come up with on the Democrats’ behalf:
…and even then it requires a Hail Mary play: write off OH, FL, & VA (all three of which have gone strongly for the GOP on the state level since 2008); retain CO, NV, & PA (that last one will be a bear, but they could do it). Also retain IA… and somehow suck two EVs out of NE. That keeps the EV at 270. A bare win. That is the Democratic firewall. That, to use a pop culture phrase, should be the Democratic party’s zombie plan.