I'm surprised you've left out nukes. Nukes are basically the only existential risk angle that presidents have direct control over and where the personality of the POTUS would effect the outcome.
1) Which one is more likely to engage in a nuclear preemptive strike?
2) Which one is less likely to forgive a 'finger slip'? (Ex, a fuse breaks in Russia/China/whoever and they alpha-strike the US; which person is more likely to retaliate and end the world vs not retaliate and suffer US extinction without punishing them back?)
3) Which one has less fear of human extinction? Religiosity and belief in anthropogenic changes to the state of the world seem to be relevant factors.
Note that what we want isn't just a President who would be likely to forgive a "finger slip", but a President who is believed by other nuclear powers to be unlikely to forgive one. I'm not sure it's possible to deliberately select that combination.
Don't let your minds be killed, but I was wondering if there were any existential risk angles to the coming American election (if there isn't, then I'll simply retreat to raw, enjoyable and empty tribalism).
I can see three (quite tenuous) angles:
But these all seem weak factors. So, less wronger, let me know: are the things I should care about in the election, or can I just lie back and enjoy it as a piece of interesting theatre?