1916 was a close election after between Woodrow Wilson and Charles Evans Hughes. Hughes was just as confident as Mitt Romney that he was going to win but lost by just over 3% of the popular vote. Hughes went to bed election night thinking he had won. A reporter telephoned to interview Hughes. He was told (as Doris Kearns-Goodwin tells it) "the President-Elect is sleeping" the reporter responded "when he wakes up you should inform the President-Elect that he is not the President-Elect anymore." That election was followed by the landslide of 1920 by Warren G Harding who promised a "return to normalcy" under prohibition with the US not participating in the League of Nations.
Could this happen today as two states, Washington and Colorado, actually voted to legalize marijuana this year? The battle now turns to the states and the humdrum of budgets and foreign policy. In my home state of Pennsylvania Governor Tom Corbett is under pressure from the right not to implement the Affordable Care Act (aka. Obamacare) and may be forcing the faculty of the state's 14 publicly owned universities into a strike affecting over 120,000 students. Nationally a high stakes debate on the budget has begun between Obama and Congress (the 'Fiscal Cliff') and wars in the Middle East and Afghanistan which strangely resembles the political chess game in the new Spielberg movie on Lincoln which covers a similar topic. What happens next depends on what happens now.
Some are predicting an apocalyptic event on Dec 21 of this year. This qualifies as a scientifically testable theory as it can be proven true or false, just as Nate Silver's forecast on the outcome of the election was. Though with a much lower probability of success.