Hold up Bryan -
I think you are discussing a 51% attack - because the #Bitcoin network can't be taken down - there are probably over 20,000 Nodes running right now - all over the world.
IF there is a 51% attack - it will be very energy intensive, and the reality is we will know it's coming before it happens. This is not going to be a simple take down.
Furthermore - do you really see China and the USA/DOJ collaborating to take down Bitcoin? To what end? Then who wins? China or the USA? Why would they work together?
While anything is possible - the earth could explode tomorrow from an internal malfunction too - or the sun could explode and wipe out the solar system. We have to entertain any and all possibilities but ignore those that are even more remote than guessing someone's keys (which would require winning the PowerBall Lottery 9 times in a row). Clearly not a threat....