What are the chances that VP Palin would have to take over from POTUS McCain, following his death or disability? Mark blogged a fortnight ago calculating an estimate of 21% from general demographic data. Nobody SFIK has shown him to be wrong.
That’s not the only possible line to pursue.
Jerome Karabel on Huffpost looks to history:
It seems almost certain that the 21 percent figure — the proportion of presidents over 220 years of American history who have not completed their term in office — is on the low side. Given Senator McCain’s age, medical history, and the very real possibility of a debilitating episode that would leave him unable to fulfill the duties of the office, the chance that the election of Senator McCain would mean a Palin presidency might be conservatively estimated at more than one in four. (my emphases)
Karabel is counting two term presidencies here. Like Mark, I think we should limit the exercise to a single term. John McCain would be unlikely to run for a second term and anyway elections are about one term at a time. A Palin candidacy in 2012 would be a new ball-game; her character flaws would still be there, but not her ignorance. [Update: OK, Mark, not all her ignorance.] The proportion of presidential terms, as opposed to presidencies, that were interrupted by a VP’s succession was 9 out of 55, or 16.3%.
The other problem with the historical data is that medical care has improved enormously. Presidents Harrison and Taylor died of simple infections that would surely be curable now; Harding of a heart attack and FDR of a stroke, which might be preventable. If we exclude Nixon’s resignation from scandal as sui generis, we are left with the four terms ended by assassinations, 7.3%.
The third approach is to make an actuarial estimate that takes account of individual characteristics. Chris Wilson of Slate’s Trailhead has helpfully run to earth an Atlanta firm of actuaries that specializes in such tailored estimates of “health expectancy”, defined as “the ability to function lucidly and without assistance”; as Slate says, “the kind of qualities one hopes for in a president”. Bragg Associates estimate that the risk that John McCain would not reach the end of his first term in decent health is 16.7%. (For Obama it’s 6.8%). Bad health in their sense might not formally trigger a succession, but would surely require a very significant role for the VP.
This strikes me as a better-quality estimate than Karabel’s or Mark’s. But it doesn’t take into account the risk of assassination that is peculiar to the Presidency – governors, senators and even Veeps seem pretty safe. There’s no reason to think this danger has gone down. On top of the baseline risk from domestic lunatics, the next President, of a polarized country in economic turmoil, will take office in the middle of a struggle with terrorists who certainly include assassination among their tactics. I propose to add the historical assassination risk to Bragg’s inverse health expectancy, making 24%.
One in four it is.