I think no amount of geopolitics PhDs will reduce the chance of wiping out humanity through nuclear war more than Mars colonization does.
I think it may take some time - centuries even - for colonizing Mars to "pay off" in terms of reduced extinction risk. But I think in the long term - say 500 years from now - we will indisputably be safer as a species if we started colonizing Mars 500 years ago than if we didn't. And if we don't start now, then when?
There is no vaguely plausible scenario where humanity goes extinct through deployment of the current nuclear arsenal. I would put the probability at zero.
I would increase that number if someone could tell a story with even a whiff of truth about how it could happen.
I think it may take some time - centuries even - for colonizing Mars to "pay off" in terms of reduced extinction risk. But I think in the long term - say 500 years from now - we will indisputably be safer as a species if we started colonizing Mars 500 years ago than if we didn't. And if we don't start now, then when?