Earlier quoted context omitted.
> if you don’t touch your coins, no one can take them away from you. (A 51% attack can’t reassign coins.) it can't generate new unsigned transactions but it can roll back the network to a state when someone else owned those coins. from a practical perspective there is no difference, you no longer have those coins.
there's a limit to how far it can roll back the network, it probably wouldn't be able to roll back more than a few days..
Let's say the US Government started a side-chain starting at the very first transaction and has kept it within it's own firewall, and has been mining for years at optimal difficulty levels so that they have to put in the least amount of work. Which now that I think about it, would just be difficulty 1, and the only reason to go above difficulty 1 would be because you started after the original chain, and you would only up the difficulty right before you were going to release it to the public.
Could they at any moment open it up and everyone would move over to their chain since it is the longest, where suddenly the US Gov owns every single coin and there's never been a single transaction?