While acknowledging that she could be wrong, McArdle defends her prediction that there’s a 70% chance that the GOP will win the White House and both branches of Congress in 2016:

Since the Civil War, only two Democratic presidents have been succeeded by another Democrat. Both of them–FDR and JFK–accomplished this by dying in office. Since World War II, only four presidents have been succeeded by a member of their party. As I mentioned above, two of them accomplished this by dying in office. One of them accomplished this by resigning in disgrace ahead of his own impeachment. Only one of them, Ronald Reagan, left office at the end of his appointed term and was succeeded by a duly elected member of his own party. Mostly, the White House flips back and forth like a metronome.

Nate Cohn responds by crunching some numbers, concluding that Republicans have a 23% chance of winning both the presidency and both houses:

This is all for illustrative purposes and it isn’t close to perfect. These numbers are outright arbitrary. Some numbers are just missing: Surely the Democrats have some chance of winning the House, and surely the GOP has some shot to take back the Senate in 2016, even if they don’t win it in 2014. But the point is that the GOP doesn’t have anything close to a 75 percent chance of holding all three branches by 2017. Not even close.

Bernstein examines the history books:

First of all, look at how many times the pattern has recurred. In McArdle’s case, we’re talking about times when a president stepped aside (making a same-party succession possible). That happened in 1952, 1960, 1968, 1988, 2000, and 2008. So her pattern, to begin with, is one out of six. That’s perhaps something…but it’s not exactly an Iron Law of Politics, is it? 0 for 10, or 1 for 50, would be a lot stronger.

Then, next, we can check the qualifiers to see if they’re making the pattern look stronger. In this case, there’s one: postwar. If we put that aside and go with “20th century,” then we add 1908, 1920, and 1928 — and get two hits, with TR/Taft and Coolidge/Hoover. Is there some special reason that the postwar era should be different? Not that I can think of, and if we include those the pattern drops to three in nine — hardly something to get worked up about. Note that the more qualifiers you toss in, the more likely you are to be creating the pattern that you’re seeing, so this is an important test.

And Larison points out the danger of Republican overconfidence:

[T]he problem with expecting anti-Democratic voter fatigue in 2016 is that it could delude many Republicans into thinking that they can get away with running another ill-suited nominee with more or less the same uninspired and irrelevant agenda that Romney offered voters last year. One of the things that harmed the Republicans in the last presidential election is that they assumed that they were “supposed” to win because of economic factors. This conveyed the message they felt entitled to winning the election, and it confirmed that they were oblivious to the modest improvement in the economy. Depending on the state of the economy in 2015 and 2016, Republicans may end up setting themselves up for disappointment again if they assume that a majority will be eager to throw the other party out.

McArdle responds to critics here and here.