The US government would only have power to shutdown exchanges running on servers hosting in the USA. Any other exchanges would have to be shut down by the appropriate country their hosting recides in. Obviously USA would and could try to pressure them into closing it, but that would be a gamble at best.
A Gamble? I think the US Government still has enough firepower to be very persuasive.
Thanks
TW
Of course. Bitcoin is such a threat the US is going to engage in a shooting war to force other nations to shut down exchanges. Shit if they did that Bitcoin would probably be $329,038 USD per BTC because it would be downright proof of the power of Bitcoin. Nobody spends bilions going to war to destroy something which doesn't matter. We didn't see the great
Flooz War of 1999 for example.
If the US banned exchanges it would simply push them into offshore locations (which have long since flipped the bird at the US when it comes to banking regulations). In the short term that would be negative, BTC price would likely tank overnight, but longer term BTC would emerge even more powerful and people would point to the failed US action as both a sign of the threat that BTC represents to the established powers and the resiliance of the global network.
I doubt the US would make a move like that. Regulate and tax is far more effective than ban and lose all control.