Since we are speaking hypothetically...
IF I were in charge of a country with nuclear arsenals, I would dismantle all ground-based ICBMs and use them to construct tactical sized weapons, with yields of 10 kilotons or less, and neutron and EMP weapons. These weapons would be placed in the control of my theatre commanders with strict RoE placed upon their use, like being overrun with no option, or to stop a break-through when no reserves existed to contain it. Enemy use of tac-nukes would allow a response in kind under these RoE. I would maintain a strategic reserve of missiles on subs as a deterrent against population bombing. These SLBMs would only be used as counter-force weapons, to obliterate ICBMs in-silo as a pre-emptive measure. Naturally, I would need a LOT of SLBMs...
This re-arming would have to be done in stages, naturally. One cannot disarm completely while making new weapons. I'd do about 10% of my arsenal at a time.
The RoE and existance (but obviously not location) of my deterrent force would be made public knowledge, in the hopes that no one would force me to use these weapons.
Note that under no circumstances would I ever order an attack on a populated area, unless that population was at least 80% military. Were the enemy basing his missiles in his cities, I would order a conventional pre-emptive strike before they could be made ready to fire, preferably while they were in transit. I simply will not tolerate using citizens as human shields against attack or retaliation.
Should he manage to make the missiles ready to fire via an intelligence failure, I would order his immediate assassination, while delivering a nuclear ultimatum to his nation. Should he remain in control, or the assassination fail, conventional weapons delivered by coordinated stealth fighters would be used to eliminate his weapons. Failure of this effort would almost certainly precipitate an armed conflict. At that point, those missiles would either be used or not.
Should any nation or group use WMD on my civilian population, our only response would be to expunge that entire civilization from the planet unless its own citizens immediately staged a revolution to replace their government within two hours of the attack. This policy would also be made public, along with our guarantee to assist any such revolution with the full array of military force at our command. Should the revolution fail, the civilization would be expunged from existence.
If they use tactical weapons against my armed forces, then response in kind will be part of the RoE, and my theatre commanders will already have their orders to fire if fired upon.
In short, my policy is designed to make other nations realise that WMD are no longer a viable option, except as cultural suicide, and that no war against my nation could be won, except as a Pyhrric victory in which both sides were exterminated. Either war would be obsolete real fast, or there would be one last brief war, with no winners.
Given human nature, I'd say it would be best if I were not placed in charge of a nuclear arsenal...
