No they couldn't. They could hurt our economy, but only at the cost of destroying their own.
I guess I am not so sure of that. While it would hurt them for a short period, they have the surplus of money that it would hurt us far worse. I read somewhere that one of their old leaders once said to be patient and bid their time and basically, they'd do us in through other means. Then there was the nut the other day that said if we went to Tawains aid, they'd nuke us.