I would argue that despite not being military doctrine, it has been effective. Nuclear deterence is demonstrably real. It is a form of Nash equilibrium. I am

I would argue that despite not being military doctrine, it has been effective. Nuclear deterence is demonstrably real. It is a form of Nash equilibrium. I am not sure there is any limited nuclear exchange that is not so risky as to be worthless unless you just want to die. Space based nuclear weapons do not improve your survivability. Space based nuclear missile interception might - if you could pretty much ensure you could take out the majority of your opponents missiles (star wars). The problem there is it destabilises the Nash equilibrium of MAD and makes it more likely someone will initiate a first strike before your defensive capability is complete...