What are the odds of a SCOTUS vacancy by November 2015 and November 2016?

Last spring, Jon Chait pointed out that if the Senate flipped to the GOP in November, this would have no significant short-term legislative consequences (with the House under GOP control no major legislation was going to be passed during the remainder of the Obama presidency in any event), but that such a flip would have profound consequences for presidential appointments in general, for potential SCOTUS nominations in particular, and for nominations to replace a right-wing justice in even more particularity.

Given the gradual breakdown of informal political norms regarding presidential appointments, and especially SCOTUS appointments, it’s now arguably become game theory 101 that no GOP-controlled Senate is going to allow Obama to appoint a SCOTUS justice at any point during the last two years of his presidency, and this is especially true for an appointment that would flip the SCOTUS, by replacing anyone other than Ginsberg, Breyer, Sotomayor, or Kagan:

It may seem implausible that Republicans would simply refuse to allow Obama to appoint any justice to such a vacancy. That is only because things that haven’t happened before are hard to imagine. But such a confrontation is not only a logical outcome but the most logical outcome. Voting to flip the Supreme Court would be, if not a political death warrant for a Republican Senator, then certainly taking one’s political life into one’s own hands. Politicians do not like political death warrants — certainly not for the benefit of the opposing party’s agenda.

The modern pattern in American politics is that tactics that are legally available, but never used for reasons of custom, eventually become used. The modern pattern is also that the Republican Party, which is the most ideologically cohesive and disciplined party, leads the way. McConnell did not create this pattern, but he is an important innovator.

McConnell was among the first political leaders to grasp that Republicans had everything to gain and nothing to lose from withholding support for every major element of Obama’s agenda — that the old Beltway folklore, which warned the opposition party that voters would punish them if they appeared obstructionist, had no basis in reality. Most people pay no attention to the details of policy, and form rough judgments on the basis of how much noise and controversy rises out of Washington. “It was absolutely critical that everybody be together because if the proponents of the bill were able to say it was bipartisan, it tended to convey to the public that this is O.K., they must have figured it out,” he confessed. Political scientists understood this reality perfectly well, but it was utterly strange to the old-line purveyors of Washington conventional wisdom. McConnell moneyballed the Senate.

It stands to reason that if and when new powers are laid at his disposal, McConnell will once again deploy them creatively. A potential Supreme Court crisis, in which the Senate simply refuses to let the president fill a vacancy on any remotely normal terms, is one possibility. Others may be brewing at this moment deep within McConnell’s extensive imagination.

What are the odds that such a vacancy will occur? This of course has to be a speculative calculation, but it’s far from completely speculative. We can begin with the general actuarial probabilities that one of the SCOTUS justices will die within the next year, or the next two years (The distinction is important because the practical consequences of, say, a potential 20-month vacancy on the SCOTUS are very different from those of a three or six-month vacancy).

While it’s true that population-wide probabilities are of limited value in regard to particular individuals, it’s also true that the various reasons one can come up with as to why they aren’t going to be accurate in a particular case tend to cancel each other out. For example, the SCOTUS justices are in the American upper class, which means that all other things being equal their life expectancies are better than those of Americans in general, but on the other hand they are doing high-stress work, especially in comparison to most geriatric individuals etc. etc.

Anyway . . .

Approximate probability of at least one SCOTUS justice dying by November 2015: 22.5%

Approximate probability of at least one SCOTUS justice dying by November 2016: 36.8%

Approximate probability of at least one conservative SCOTUS justice dying by November 2015: 14%

Approximate probability of at least one conservative SCOTUS justice dying by November 2016: 26.2%

Of course to the extent these probabilities are accurate, they establish a floor for possible SCOTUS vacancies. They must be enhanced by the odds of a justice retiring for health or other reasons, which are naturally far more speculative. If we assume the combined odds of all such events are equivalent to even half of the mortality risk currently faced by members of the American Politburo Supreme Court, then the odds of a SCOTUS vacancy during the remainder of Obama’s presidency rise to just about 50/50, and the odds of a swing SCOTUS vacancy arising with more than a year remaining in Obama’s term are better than one in five.

Would the latter circumstance lead to the SCOTUS having only eight justices (or less) for more than a year? I agree with Jon that the answer to that question is almost certainly yes. Whether that would create some sort of political or constitutional crisis is another question, regarding which I don’t have an opinion at the moment.