Nuclear Weapons, the Centre and the Right
So, lots of points here, so thank you everyone.
The first thing I would like to note is that no one seems to be engaging with one of my main interests - are there many conservatives who are also advocates of nuclear disarmament?
To move onto the responses - Given that my main concern here is avoiding Nuclear armageddon, I don't think I could have an objection to some powerful nation (at least powerful in a kind of crude, violent sense) creating an impregnable weapons system. Even if it only protected a reasonably large part of the world, that would be part of the world. I don't really agree with one, or a group of countries, having this kind of pre-eminent position, but in terms of long term species/biosphere protection, beggars can't be choosers.
It may be utopian to get rid of the nuclear weapons. Looked at another way, it may be utopian to have the kind of world-wide social change which would probably be required to remove the incentive from states to develop or keep such arms.
However, I don't think the response to this is to say "We will never get rid of nuclear weapons, therefore it's best that my country keeps nuclear weapons." You need additional premises to claim that, in your country's hands, they will never be wrongly used. I don't think it's easy to claim that.
Another point is that: no leader, even despotic ones, want to kill millions of citizens of opposing nations. Why not? Because strategically it makes no sense. You don't want to get into that situation - you want to win out, or at least reach a stalemate, without this happening. Because if you are in that situation, you are already in extreme danger. The reason I'm saying this is that it's a lazy gloss to see even dictators in these terms. For the vast majority of cases, even if these people are insane, they aren't malicious in this way, but rather ruthless and paranoid. It plays into a simplisitic good and evil narrative to say this - where as the more nuanced good and evil is when we see that we, as easily as the enemy, may be the source of the evil. In my world view, with regards the current situation - which I don't want to focus on, admittedly - both Russia and NATO are both my enemies, because both possess the power and the motivation to use these weapons if they deem the situation warrants it. But they are mutually enforcing each other in this regard, and so they are both responsible. I would fight in a war against an agressive Russian Federation without these, but I won't fight in the current situation, as I don't believe you can justly - or even rationally - fight for a side which is willing to use weapons of mass destruction.
The sad thing in this, for me, is that people are currently being sold the idea that nuclear weapons keep them safe. They do not. If they go up, it's the end of Europe, North America, and Asia, at least. Fighting a war - even losing a conventional war - is nothing in comparison. The costs on the latter are genocide, displacement, massive casualties plausibly, loss of some or all homeland. But the alternative is literal obliteration.
I won't comment on the technicalities of whether a missile defence system can work or not - I was a moral philosopher, not a ballistics expert.