And their risks as well.

IMHO, the reason is not really to protect US manufacturers. It is about long-running negative balance of trade between US and the rest of the world.

Protectionism rhetoric is a sugar-coat for Americans who will have to foot the bill by paying more for imported goods, but honestly, who else should?

https://en.wikipedia.org/wiki/United_States_Balance_of_trade

I guess this may happen if browser doesn't accept third-party cookies.

This propagation delay does not really matter as long as neighboring power plants are synchronized with each other.

Yes, east coast and west coast are out of phase, but only to a perfect observer who can see phase value on both coasts instantly (without a propagation delay). However in reality information about the phase cannot travel faster than speed of light, so to any real observer anywhere between east and west coasts both sides appear to be in sync.

If the ledger is centralized, what is the advantage of using blockchain?

probably none. that is a different discussion. there were many better solutions than http for the web, hotly debated, but http became the defacto standard. betamax vs vhs. lots of reasons why inferior technology sometimes wins mind/market share

i dont drink the blockchain kool aid myself as a silver bullet for every problem, read IBM's hyperledger marketing materials and they try to make a case for centralized permissioned blockchain. ymmv.

but if millions of your citizens are using blockchains, as an authoritative regime, you probably will want to control its use. you arent particularly interested in the best tech solution to a problem. just control.

and lest anyone think i am abusive of china, i fully expect the US to highly regulate the hell out of this eventually ... if not now under the Tweeter in Chief, when the Dems get control again.

There are regulations for casinos as well.

When breaking with engine, the kinetic energy of movement is converted to heat not via friction (like breaks do) but via compressing air in cylinders which does not cause extra wear on anything.

I think you're referring to "Jake Braking", which is very noisy and is banned in many towns (in California).

https://en.wikipedia.org/wiki/Compression_release_engine_bra...

"Jake Braking" is similar, but pertains more to diesel engines which have a special valve to support this since they work differently.

Engine braking on a gasoline engine is actually quieter than normal operation.

At least the manufacturers of those products assert that correctly installed ones are no louder than the diesel engine in normal operation.

http://www.jacobsvehiclesystems.com/about-us/environmental-h...

What about Opium wars?

One country using military force to coerce another country into trading with them does not constitute a free trade agreement. Free trade agreements are consensual.