... or as the Cook Partisan Voting Index has it by states and relevant districts:
R+20 or more.... WY, UT, NE-03
R+13 to R+19
R+10 to R+12
R+5 to R+9 (biggest by far: Texas)
R+1 to R+5
R+0 (OH, FL) or D+0 (CO)
D+1 to D+4 (biggest: PA, WA, MN, WI)
D+5 to D+9 (most notably CA, IL, MI, and NJ)
D+10 to D+15 (HI, MA, ME-02, NY, RI)
D+39 (DC)
(ME-02 should appear as orange)
Relevant elections are 2004 and 2008.
It's easy to explain how the Democrats could win: they would of course win
3 EV (District of Columbia) in maroon
54 EV in red ( 57 cumulative)
104 EV in pink (161 cumulative)
108 EV in orange (269 cumulative)
...which in 2008 was enough in the event that enough Congressional delegations had Democratic majorities. In 2012 such won't be enough in view of re-districting. Those are states voting clearly (even if slightly) more Democratic than the average between 2004 and 2008. Colorado, marginally more Democratic than the US, could be necessary just for a tie in 2012.
Florida was the margin of electoral victory in 2000; Ohio was the margin of victory in 2004. The two states, different as they are, generally move together. The Republicans absolutely must win both in 2012, and the Democratic nominee of 2012 need win one as well as everything in any shade of red and in orange to win. Both states are easier to win under normal conditions than anything in aqua or any shade of blue.
The states in tan comprise 56 electoral votes. Obama won these and their 56 electoral votes. On Election night, most people recognized that the contest was certain once the networks called Ohio for Obama fairly early. They were slow to call some other states, some (like Virginia and Colorado) that they didn't know so well.
Six states are in the aqua group -- Arizona, Indiana, Missouri, Montana, North Carolina, and Virginia. Obama won three of the six, which is remarkable. If he is at all successful as President he wins all six of them in 2012 if nothing else "beyond" this stage. These states comprise 63 electoral votes. The Age Wave alone suggests that Obama will solidify his wins in Virginia (which may be drifting into the Blue Firewall), Indiana, and North Carolina. Most people recognize Missouri and Montana as the most likely pickups for Obama in 2012. Arizona would have been close in 2008 except that John McCain was the Presidential nominee.
Two states (Georgia and West Virginia) and one district that counts (NE-02) are in light blue, and they comprise 21 electoral votes. Obama won NE-02, a surprise to many. In 2004 it was far from contested; in 2008 it was. Obama will likely win NE-02 in 2012 unless the state legislature reverts to a winner-take-all plan just due to the Age Wave. Georgia young adults are much more conservative than those of the nation as a whole, and West Virginia has drifted strongly Republican from having been one of the most reliable states for the Democrats. Should Obama win either Georgia or West Virginia, then he will have done something to go beyond the effects of the Age Wave.
States (and NE-01, eastern Nebraska except for greater Lincoln) in medium blue are more unlikely to go to Obama in 2012. They have been firmly Republican for years or are the states that Clinton could get but Obama couldn't. Of these, ND, SD, and SC were closest in 2008... don't bet on them unless you get long odds.
Darker shades of blue involve states and especially NE-03 (central and western Nebraska) that Obama could win only if freakish things happen. For Obama to win Utah the Republican nominee would have to denounce Mormonism as a "demonic cult". I think that you get the idea.
For the Republicans to win they would have to win everything in any shade of blue, in aqua, and tan, accounting for 269 electoral votes (probably more and a clear win in 2012) . Such are all the states that George W. Bush won in both 2000 and 2004 except for Nevada. Nevada drifted strongly Democratic in 2008 after being a slightly-Republican-leaning state for decades, the sort of state that Democrats might win in a 360+ EV victory. Nevada is the sort of state that the Democrats could win in a close election. (Forget discussions of wins for either party with 305-360 EV -- there have been none since the nineteenth century).
Iowa, New Hampshire, and New Mexico would seem rather shaky in a close election, but bare majorities in popular votes are likely enough to keep them in the Democratic column. Gore lost New Hampshire despite winning the popular vote in 2000 and barely won Iowa and New Mexico; Kerry won New Hampshire despite losing the popular vote (Kerry lost Iowa and New Mexico barely while coming close to losing Wisconsin). States in orange (and ME-02, central and northern Maine) comprise 81 electoral votes. A Republican who wins all the states in blue, aqua, tan, and orange wins 350 electoral votes if winning the election 52-48.
Nobody has won the Presidency with 350 or so electoral votes since the nineteenth century. To do as well as Obama did in 2008, the GOP nominee must win Michigan and its 17 electoral votes. That's 367 electoral votes to be had by winning what looks like the shakiest state in the hard core of the Blue Firewall. The GOP hasn't won any such election in a long time. But getting all 131 EVs from states in the pink category GOP nominee gives the Republican nominee 481 electoral votes, which is roughly what George Herbert Walker Bush won in 1988. States include not only Michigan, but also California, Illinois, New Jersey, and Maryland.
The next tier suggests a Democratic disaster, with as many as 54 of the last 57 EVs going Republican. No Democrat has won fewer than 13 electoral votes -- 17 for McGovern in 1972 and 13 for Mondale in 1984. There will be at least some Favorite Son effect to cause the Democratic nominee to win something other than the District of Columbia.
There's nothing between D+15 and D+35. The District of Columbia goes Republican only if the incumbent President is being impeached for murder or something to that effect, or the Republican Party runs unopposed.
