Earlier quoted context omitted.
I always considered that if you believe nuclear deterrence is effective, it would be logical to disband the entire conventional military, and keep the nuclear weapons. The advantage would be you save an enormous amount of money, and vastly reduce the size of government. Politicians will stop being tempted to invade and interfere in other countries, and grievances against your country are reduced or eliminated. The lo…
Ah, but you always have another choice. You can always surrender. Now, sure, you might be unwilling to surrender, and willing to risk a global nuclear war, over a direct invasion of your homeland. But what about, say, a covert invasion of a remote ally under the pretext of peacekeeping? What about military support for a coup in a nearby ally? What about a gradual strangling of your trade and resource routes? Are you…
The thing is that there is no reason to believe that a nuclear exchange is necessarily the same as national suicide or will escalate to a global nuclear conflagration. The political scientist Ken Waltz made this point quite forcefully (https://www.mtholyoke.edu/acad/intrel/waltz1.htm): even if one or two nuclear bombs are exchanged, there is still every incentive for the parties to calm down. What nuclear weapons do is vastly increase the risk and cost of starting a war. This is good, as wars start when politicians believe the cost is worth the benefits.
Waltz says:
"Nuclear weapons in the hands of six or seven states have lessened wars and limited conflicts. The further spread of nuclear weapons can be expected to widen those effects. Should the United States then promote the spread of nuclear weapons for the sake of peace, even though we need not for the sake of stability? To do so would replace one extreme policy with another. Present policy works hard to prevent additional states from acquiring nuclear weapons. My examination of the effects of nuclear weapons leads to the conclusion that our policy is wrong without supporting the proposition that true proliferation—the rapid spread of nuclear weaponry—is desirable. Rapid change may be destabilizing. The slow spread of nuclear weapons gives states time to learn to live with them, to appreciate their virtues, and to understand the limits they place on behaviour."
> But what about, say, a covert invasion of a remote ally under the pretext of peacekeeping? What about military support for a coup in a nearby ally?
The solution, as per Ken Waltz, is to promote the proliferation of nuclear weapons. Your remote ally should also have them!
> What about a gradual strangling of your trade and resource routes?
This would be generally considered an act of war (what the US did to Japan pre-WW2, actually; and Nixon considered an oil embargo from the Saudis equivalent to an act of war). The critical thing is to make it clear where you are drawing the lines.
> Are you EVER going to say "ok, THIS is the last straw, we're starting a nuclear war NOW because you blocked all roads to Berlin"?
The United States should not start any kind of war over what happens in Berlin. But German people themselves should certainly have nuclear deterrence.
> It's like wearing a suicide vest for personal defence.
It is a lot more like carrying a gun for personal defence. In human societies we have the rule of law to defend us, but in international relations it's still 'might makes right', and being willing to kill is a key part of that. Now, if you are a mugger, would you be more willing to attack someone who is willing to use a gun and has no other alternative, or to attack someone who is very reluctant to use a gun and will give up their wallet if pressed? Exactly.