>As for outright prevent spare parts - these aren't systems in, well, active use. Effects would be tiny over long term.

Experts disagree with you, at least over the "long term".

>Margaret Thatcher’s cabinet secretary, Robert Armstrong, told her that “in the inconceivable case of a future US government deciding to cut off supplies of components”, there would be “no sudden effect”, though over “two or three years” the deterrent’s effectiveness would “begin to fall off”. In 2006 Commodore Tim Hare, a former nuclear-policy chief at the Ministry of Defence, told the Commons Defence Committee: “If, over a very long period, we became deeply estranged from the Americans and they decide to rat on their agreements, we would be in…great difficulty.” But the risk was “very low”.

>Sir Lawrence reckons that were that to happen there would not be a “cliff-edge” loss of effectiveness, “but over time we would be scrambling to keep it going”. The biggest problems would be replacing the Kings Bay missile storage and running out of critical spare parts.

https://archive.is/Qz2lI

They're almost saying what I said? Effects only in the long term, and even then they may be able to manage ('scrambling').

Your original claim:

>Effects would be tiny over long term.

The experts I quoted:

>over a very long period, [...] we would be in…great difficulty

>over time we would be scrambling to keep it going

"great difficulty" and "scrambling to keep it going" isn't "almost" the same as "Effects would be tiny "

I'll grant that, though I think that when countries want nukes they get/keep them unless strongly opposed (and usually even then...) - so I don't think US can deny the system in practice.

> Any backdoor could be in theory found by an enemy

In theory.

In reality, it took Snowden leaks for some of the smartest and most motivated people working in technology to discover they had been backdoored by a third-party.

My understanding of the article is that it was about shutting down the program that keeps the nuclear navy afloat, not about a backdoor with a switch to turn off the arsenal

Backdoors introduced by competent people require authentication, so that random people or "the enemy" can't use them.

Competent spies and hackers try to get in nevertheless, and can succeed. Risk is not insignificant if these exist.

I suspect that US has kill switches in place to ensure that their tech cant be used against them. Should they come up against F-35s they sold to another nation, it would make sense to have a mechanism, unknown to the purchaser, that would render it usesless against the US.

The US launch codes were 00000000. The same people that did that aren't worrying about the risk of backdoors.

https://arstechnica.com/tech-policy/2013/12/launch-code-for-...