I'm well aware that past performance is not necessarily indicative of future results, but there is a noteworthy trend in American politics going back to 1860: The 36-year political cycle.
Like clockwork, every 36-year period from 1860 onward has contained the dominance of a particular ideology; 28 years of Presidential dominance by one political party; and 8 years under the control of a moderate President of the opposite party.
You may notice that we're 148 years removed from 1860, and 36 doesn't divide evenly into 148; you have 4 years left over. Those 4 years correspond to Jimmy Carter's term, which I believe was a fluke brought about by the unprecedented events of Watergate. (Despite Watergate, he still only managed to squeak out a victory over Gerald Ford, and he lost his re-election battle badly.)
Cycle #1: Civil War, Reconstruction and the Gilded Age (1860 - 1896)
This period of time was dominated by the Republican Party; Presidents Lincoln, Johnson, Grant, Hayes, Garfield, Arthur and Harrison, who held the Presidency for 28 years, were all Republicans.
The Republican Party emerged from the ashes of the Whig Party. It was most famously opposed to slavery, but generally supported industrialization, high tariffs and protectionism, and an interventionist foreign policy.
The only blip in Republican dominance was Democrat Grover Cleveland, who served two non-consecutive terms as President. He came into power largely because of a fight against corruption, but he also opposed high tariffs and supported the gold standard over the silver standard.
Cycle #2: The Progressive Era (1896 - 1932)
This period of time was again dominated by the Republican Party, but the party bore little resemblance to its previous incarnation. McKinley was voted in on a platform of keeping the gold standard (borrowing a page from Cleveland) and despite his support of high tariffs, he was ardently pro-business.
The era didn't really get into full swing until McKinley's assassination and the assumption of Teddy Roosevelt to the Presidency; he brought about significant business regulation. His chosen successor, William H. Taft, was promised to be another progressive, but wasn't up to the task; he was defeated by a Democratic progressive, Woodrow Wilson. Wilson, in turn, was succeeded by Harding, Coolidge and Hoover; although they supported workers' rights like previous progressives, they also supported serious deregulation that led to the Great Depression.
Cycle #3: The New Deal (1932 - 1968)
Franklin Roosevelt fought the Great Depression with a serious of social programs, many of which remain today. He served for an unprecedented four terms and was followed by fellow Democrat Harry Truman. Truman, unfortunately, overreached with his so-called "Fair Deal" and made several mistakes in the Korean War; he wasn't renominated by his own party and was followed by Eisenhower, a Republican who nonetheless was a fan of the New Deal.
Eisenhower was followed by Kennedy and Johnson. The latter, unfortunately, was bogged down by Vietnam; in 1968, he wasn't renominated by his party and the Democratic party faced defeat.
Cycle #4: Goldwater's Coattails (1968 - 2008?)
Barry Goldwater was defeated in a landslide in 1964, but some of his policies started taking root. Richard Nixon was, by today's standards, pretty liberal; but he also led the reaction against the excesses of LBJ's great society and the successes of the Democrats in the Civil Rights Movement.
Following his resignation, Gerald Ford took over; his defeat in 1976 is the one hiccup here, as Jimmy Carter was elected in no small part due to Watergate and Ford's pardoning of Nixon. 1980 returned things to "normalcy" with the enormous electoral success of Ronald Reagan, who formed an unholy alliance of Goldwater's anti-government agenda and the religious right. His successor didn't turn out to be so popular, and he was defeated by a moderate Democrat (who has been humorously described as the closest thing to a moderate Republican since Eisenhower).
Al Gore wasn't able to carry Clinton's momentum, however; we're now treated to a Republican President, who like Cleveland, Hoover and LBJ (the last presidents of their respective eras) seems to be going down in flames.
We'll see in less than a week if we have the possibility of another 36-year cycle, this one led by Democrats.