Political Roko's basilisk

But that's not Roko's basilisk. Whether or not *you* individually vote for the candidate does not affect you as long as the candidate wins.

Against improper priors

The "Dutch books" example is not restricted to improper priors. I don't have time to transform this into the language of your problem, but the basically similar two-envelopes problem can arise from the prior distribution:

f(x) = 1/4*(3/4)^n where x = 2^n (n >=0), 0 if x cannot be written in this form

Considering this as a prior on the amount of money in an envelope, the expectation of the envelope you didn't choose is always 8/7 of the envelope you did choose.

There is no actual mathematical contradiction with this sort of thing -- with prior or improper priors, thanks to the timely appearance of infinities. See here for an explanation:

https://thewindingnumber.blogspot.com/2019/12/two-envelopes-problem-beyond-bayes.html

Interesting. Did they promise to do so beforehand?

In any case, I'm not surprised the Soviets did something like this, but I guess the point is really "Why isn't this more widespread?" And also: "why does this not happen with goals other than staying in power?" E.g. why has no one tried to pass a bill that says "Roko condition AND we implement this-and-this policy". Because otherwise it seems that the stuff the Soviets did was motivated by something other than Roko's basilisk.