The 12th Amendment to the U.S. Constitution (which superseded a large section of Article II, Section 1) suggests says that the ballots of the electors in the several states having marked their ballots for President and Vice President shall
"transmit sealed to the seat of the government of the United States, directed to the President of the Senate; -- the President of the Senate shall, in the presence of the Senate and House of Representatives, open all the certificates and the votes shall then be counted."
On or about January 6, 2013 (probably January 7th or 8th as the 6th is on a Sunday) that counting will take place and Barack Obama will be declared President and Joe Biden will be declared Vice President.
That part we know all too well. What we don't pay much attention to is the original (and un-amended) language of Article II, Section 1 which states:
"Each State shall appoint, in such Manner as the Legislature thereof may direct, a Number of Electors, equal to the whole Number of Senators and Representatives to which the State may be entitled in the Congress"
Note, the Constitution does not prescribe that the candidate with the most votes in a given state be granted all of the Electors. It leaves the "Manner" of selection up to the State Legislatures.
Indeed, if the State Legislature of Upper Iguana determined that its Governor should choose the electors, then a popular vote would be unnecessary as he (or she) could pick electors for what ever candidate he (or she) desires.
Or, Upper Iguanians might decide to let the Legislators themselves choose the Electors.
Granted, either of these is unlikely in any real state except for Illinois, but it would be possible.
The current system is well known: 48 states and the District of Columbia award all of a states' Electors to the candidate that wins the majority of the votes in that state.
The other two states, Nebraska and Maine have a better plan: They award Electors by Congressional District. Nebraska has three Congressional Districts; Maine has two.
The winner in each CD gets that Elector and the candidate with the most votes statewide gets the Electors awarded for the two Senate seats.
I have no idea what the effects on the 2012 election would have been if all 50 states and DC had adopted that concept and it doesn't matter because both sides knew the rules going in. It does seem, though, that awarding Electors by CD would put more than eight or nine states in play every four years.
In California, which has 55 EVs, Romney would have had a shot at as many as 16 Electors in Districts likely to be represented by Republicans.
Similarly, in Texas Obama might have picked up as many as 12 of the 38 EVs available there.
The direct election of the President would likely mean that all of the attention would be paid to the high population areas: New York City, LA, Chicago, Houston, Miami and so on. The smaller cities and towns would be left out in the cold.
There may be some very good reason that I'm missing that argues against a Congressional District selection of Electors, but I can't think of it.
Not every CD would go for the Presidential candidate whose party is represented by the Member of Congress, so it is not a direct one-to-one relationship.
I understand it would make it much harder for the networks to "call" a state the moment the polls close based upon exit polls, but the method of electing a President shouldn't be designed for the convenience of the national press corps.
Over the next days or weeks researchers will have voting results that are granular to be able to determine what would have happened if the CD system were in place in 2012; but it wasn't so the two campaigns didn't design their efforts to reflect it.
The Constitution allows State Legislatures to determine the method of choosing Electors, so this system doesn't need a Constitutional amendment; it could be done in the next few months.