For all we know, the NSA has a ton of secret miners it could switch on suddenly to launch a 51% attack. Prove me wrong .

(ok this is the stuff of conspiracy theories but it's still a possibility, isn't it?)

Well I guess the question is, if the US govt (or any other superpower) felt it was in their interest to take over / destroy the blockchain, would they be able to?

It seems to me if Bitcoin got to be of huge strategic importance to global finance, countries like the US would start to build out that power. The idea that the economy of say the US was at the mercy of other foreign governments would probably not sit well.

This applies to all large powers just using the US as an example.

Uh-huh. The agencies of, let’s say, the US federal government, or the Kremlin, or similarly those of governments in the UK, France, Germany, all have no history of overseas intervention or onshore direct action to preserve economic interests. Got it.

if 51% of hash power were located in the US, the statement would have been about the US. it is not something special about china that makes this the case, only the fact that it is a sovereign state with the means and will to control activity in its territory, just like every other functioning state. one could also make the case that china might be more likely to intervene in such a way in the economic affairs of its subjects than a liberal democracy, but that is a secondary argument.

No, China is not a person with a single will. The assumption/assertion that the mining equipment may as well all be sitting under MSS guard in Beijing is horsecrap.

It does have a person that can enforce his single will pretty well, though.

In any case, you can follow it like this:

* Nations desire to control strategic resources

* Bitcoin is one such strategic resource

* To control Bitcoin, you need more than 50% of the network

* China has 65% of the network

* China can control Bitcoin

For small scale miners in China it might be a different story.

However, if Xi Jinping decided to crush Bitcoin for whatever reason large scale mining in China, which is well past 50%, would quickly do what he wanted. As such he has de facto control over Bitcoin, though I personally doubt it’s something he would do.

why do you expect that? you're talking about tens of thousands of individuals and companies, all themselves invested in bitcoin, being asked (through no existing command or enforcement mechanism) to essentially destroy their own personal wealth. even assuming the chinese state could achieve compliance from 77% of the existing hardware, it would optimistically take several days. the only way around that stumbling block would be to mandate centralized control of the miners, which would be impossible to keep secret and would also inspire some sort of reaction.

the idea that every miner in china will jump when xi says is pure fantasy.

Remember, China is a country with concentration camps, so they (the CCP) clearly have the ability and desire to do extreme things and convince their people it's the right thing or that it's not happening.

and america has the largest prison population in the world. we still have plenty of people that don't immediately comply with whatever the president says at any moment.

yall act like china is populated entirely by robots. it's a complex society just like anywhere else.

If the US sends an army to China in order to seize their mining rigs, then Bitcoin is the least of our problems.