Yes it's not unlike what happened with Poker sites but... Pokerstars, who had its Pokerstars.com seized (for a few weeks IIRC) by the FBI/DoJ is still, today, raking million of dollars daily in rake (and tournament fees) totally legally (and often with business deals with brick'n'mortar casinos) in nearly the entire world... Except the U.S.!

Should the U.S. decide to "start a war" against bitcoin just like they did with Poker, we'd end up in the same situation: servers outsides of the U.S., not using .com domain names, without the reach of the U.S.

I'm pretty sure that any Bitcoin exchanges outside the U.S. (like MtGox, BTC-E, Bitstamp... which are the three biggest ones) and their employees are shielded from U.S. laws. If they can't extrade Snowden out of Russia, I don't see how the U.S. could reach the BTC-E russian Bitcoin exchange.

The U.S. have been unable to stop online poker worldwide. Should they try to stop bitcoin worldwide, they'd fail too.

Now that said I don't think the U.S. government is going to ban bitcoin or to go on a crusade against bitcoin. At least I hope not.