John Judis looks ahead to the presidential election and offers a reason to doubt that the Democratic candidate will win:

The chief obstacle that any Democratic nominee will face is public resistance to installing a president from the same party in the White House for three terms in a row. If you look at the presidents since World War II, when the same party occupied the White House for two terms in a row, that party’s candidate lost in the next election six out of seven times.

I made a similar point recently, so I agree with Judis that voters’ fatigue with the Democrats could be a serious problem for the Democratic nominee in 2016. It could be an even greater problem for Clinton because she has nothing new or interesting to offer the voters. Of course, there is nothing magical about a party not being able to win a third consecutive presidential election. The elder Bush won in 1988, and Gore, Nixon, and Humphrey all very narrowly lost. Prior to WWII, Republicans had two stretches of continuous control of the presidency that lasted twelve years or more (1897-1913; 1921-1933), and Democratic presidents had an uninterrupted hold on the White House for five full terms. While it has become less common since the 1940s, it has happened often enough in earlier periods of U.S. history that we can’t assume that it won’t become a more common occurrence at some point in the future. That said, there are good reasons to think that the third-term issue will put the Democratic nominee at a meaningful disadvantage in the next election.

Judis mentions the accumulation of grievances over eight years in power, and that is one reason for the movement of voters from one column into another. Another is the demoralization and dissatisfaction of a party’s supporters. Following two terms that didn’t deliver as much as they had expected, or that produced unwelcome policy decisions, some voters that would otherwise be inclined to favor the incumbent party find reasons not to favor a third term in power. They may simply stay home, or they may even switch to the other party out of frustration with their own party’s leadership. On the other side, the party that has been out of power for eight years is usually much more motivated. It has the luxury of being the out-party, which means that it doesn’t have to defend and justify the record of the outgoing administration, and it can present itself to the public as a necessary and potentially refreshing change from the party in power.

The candidate from the president’s party has a harder task. The nominee has to strike a balance between endorsing most of the sitting president’s record and offering more of the same to satisfy partisan voters and criticizing enough of the same record to avoid being weighed down by the administration’s baggage. When a president has mediocre or poor approval ratings, as Obama probably will have at the end of his term, it becomes almost impossible for a candidate to find the right balance between approval and criticism. That is because it becomes much more difficult to win over alienated voters without further demoralizing one’s own core supporters. Even in cases of extreme presidential unpopularity, most candidates for the nomination don’t want to be seen as trashing or repudiating the president. Most partisans that vote in primaries remain supportive of the president at least as long as he is still in office, and so the eventual nominee has to cater to that. An added difficulty is that the presidential party’s nominee usually is very closely aligned with the administration on policy, so that it is only too easy for the other party to use the administration’s failings as a bludgeon against the nominee. That attack becomes even easier when the nominee is very closely associated with the administration or even served as a part of it.

It’s entirely possible that the Republicans will nominate such a poor and unappealing candidate that these disadvantages will be outweighed by the Republican’s flaws, but assuming that they choose a reasonably competent and likable nominee 2016 could easily prove to be another disappointing year for Democrats.