This from the Meta-Analysis site:
"Under today's polling conditions, four states are clearly in serious contention: Florida, Iowa, Ohio, and Wisconsin To a lesser extent so are NV, WV, and some others. Depending on undecideds/turnout/bias, states come into or go out of play, but in those situations Kerry or Bush typically win the Electoral College by a more comfortable margin. So let's concentrate on this near-tie condition. After assigning other states as indicated by polls (PA and MI to Kerry, MO to Bush, and so on) and playing with combinations, several patterns emerge."First - if Kerry wins Florida, the election is over - he wins. Kerry can also win by taking Ohio plus one of the smaller states. In the other direction, Bush must win not only Florida, but also either Ohio or all of the smaller states. In light of these facts, the Saletan piece indicates that the Bush campaign's actions may amount to a defensive move - otherwise why give up on Ohio?
"It's also possible to identify states that look moderately solid, but might flip if the combination of undecided/turnout/bias factors adds up. This is interesting because this shift is likely to be similar across states. Therefore these states can act as an early-warning system for a surprising election night. For instance, Arkansas, North Carolina and Virginia currently look like Bush states, and Maine looks like a Kerry state. If a surprise occurs in any of these states, this might presage a significant offset between decided-voter polls and the real outcome."