Hi David,

You bring up some interesting points but I have to disagree again on a number of issues.

A 51% attack is not only extremely unlikely, but it's also not possible even theoretically.

China had 80% of the mining operation under their control. They didn´t launch a 51% attack. Why? Because they knew it would fail.

The US doesn't have anywhere as much power to implement this kind of attack. Thank God it is a liberal democracy and a union of Federal States meaning power is divided among many actors.

Regulation is always possible and sometimes even desirable but forcing the miners to do a 51% attack on themselves is not realistic. The most the government could do is to shut down the mining operation, then the US would go from 51% to 0% and all hash power will be outside their control.

Google and Amazon had to comply with regulations but the government can't force them to change their algorithm, or reveal their knowhow and company confidential information. They rather shut down and move to Mexico before that happens. In fact, that would be unconstitutional and could never fly.

Remember when the CIA asked Apple to unlock an iPhone and they refused to do it? That's what I mean.

The same thing happens with miners, they can be forced to stop but not to attack their own network.

Besides, to launch a 51% attack a lot more than 51% of the hash power is needed. First, it needs to be done covertly and very quickly in order to avoid any leak that could alert other miners that will rush and support the blockchain in a number of ways. Second, it is extremely expensive and not profitable at all. Third, it needs a level of organization, cooperation, and consensus we have never seen before by any nation.

This is why Bitcoiners were not worried when China had 80% mining power and they are not worried now. Rest assured that a 51% won't ever happen, it's too late now, they should have done it in 2011.