I'm not sure if Kessler syndrome would prevent ICBMs - it wouldn't prevent things from getting to space, it would prevent things from getting to space safely. I

I'm not sure if Kessler syndrome would prevent ICBMs - it wouldn't prevent things from getting to space, it would prevent things from getting to space safely. If there's a 50% chance of a destructive impact, manned flights are right out, but firing hundreds of ICBMs would still be reasonably effective.