I was just reading this article about Mike Huckabee saying that President Obama’s going to be harder to beat than a lot of Republicans think. I think he’s right, for a number of reasons. But one he mentions is incumbency. And he’s right. People simply don’t appreciate how seldom elected presidents get denied reelection. By my count, it’s only happened three times in the last century. Carter, the first President Bush and Herbert Hoover. (If you come up with someone I’m missing I’ll be terribly embarrassed. But please let me know.)Before that, you need to go back to William Howard Taft and the three way GOP split election that elected Woodrow Wilson. But that’s 1912. So that’s one century ago and thus outside my century count. Before that the experiment starts to breakdown because there was more of a tradition of intentional one-term presidencies.
Now, there are some cases of presidents who declined to run — Truman and Johnson. But they’d already run and won elections as incumbent presidents, albeit inheriting the job at first. Ford, of course, lost. But he was never elected in his own right. Not even as Vice President. He was appointed to the office, after Spiro Agnew resigned.
So there’s some squishiness at the margins. But what it comes down to is that presidents who are elected tend to get reelected. The pattern is really clear.