As it happens, we have a lot of recent history on the subject. With Barack Obama's reelection this week, we have reelected 3 Presidents - Clinton, Bush, and Obama - to consecutive terms for the first time since a trio of Virginians 200 years ago.
From 1800 to 1824 Thomas Jefferson, James Madison, and James Monroe each won and served 2 full terms in office. In fact, 5 of our first 7 Presidents won reelection and had the full 8-year run.*
* To the embarrassment of the Adams family, the only two who lost reelection were John and John Quincy.
A pattern had formed, right? Nope. The next 100 years was a long sad history of lost elections, assassinations, and natural deaths. From 1836 to 1933 only U.S. Grant and Woodrow Wilson served two full consecutive terms in office. Then FDR showed up and went on a DiMaggio-like run, winning 4 Presidential elections (and yes, the Yankee Clipper had his hit streak right smack in the middle of FDR's Presidency).
But once again, Incumbent Power seems to be back in vogue. Which is curious, because second terms have been rough sledding for the past half century.
1964: LBJ & Vietnam
When Lyndon Baines Johnson easily won reelection in 1964, the tiny country in Southeast Asia called Vietnam wasn't a big election issue. By 1968, casualties were soaring, the Democratic Party had splintered into factions, and Johnson bowed out of the race (he was eligible to run again, since his first time was the completion of JFK's term).
1972: Nixon & Watergate
It's hard to imagine now, but in 1968 Richard Nixon won the electoral college vote 520 - 17! He carried 49 states. This was one popular, successful President.
But the seeds of his destruction had been sown - the break-in of the Watergate Hotel occurred 5 months before the election. In 1975, Nixon resigned in disgrace.
1984: Reagan & Iran-Contra
Reagan, too, won reelection in a massive landslide. Like Nixon, he won 49 states and over 500 electoral votes *. His second term is a little harder to judge. He left office still popular, his Vice-President easily won election as his successor, and the Soviet Union's downfall, arguably hastened by Reagan's policies, was only 3 years away.
But the Iran-Contra scandal hobbled this term. The curious part of Reagan's role in this is that his defense - that he wasn't aware of the actions taken by the Defense Department and the National Security Council - was in some ways worse than being guilty. It suggested a level of detachment that possibly presaged the Alzheimer's that was to overtake him later.
* This week, many stupid articles are being written about an 'Emerging Democratic Majority'. As I wrote in 2008, only 3 elections in U.S. history have created enduring majorities (Jefferson, Lincoln, FDR). Nixon and Reagan won much much more decisive reelections than Obama, but their party was unable to sustain the momentum, and there is good reason to suspect the Dems won't either
1996: Clinton & Impeachment
We're now fully into subjects where partisan fevers still run high, so I won't rehash the whole Monica scandal. But I think we can all agree that a term that includes only the second Presidential Impeachment in U.S. history wasn't an unmitigated success.
2004: Bush & Iraq/Economic Meltdown
You remember that one, right?
So, now Barack Obama starts his second term. Excited? Many Republicans believe they already know what will make his term a failure. Massive deficits, 8% unemployment, the pending economic impact of Obamacare, Iran's quest for nuclear power, etc.
Who knows what this term will bring?