Could never happen. Losing all shipping into the ports would put a major hole in the economy. Losing the military bases and those dependent on the military would be just more loss then they could handle.
They would be starting out drowning in debt and it would get worse when they found out how badly what ever currency they used was devalued.
Water and power would be at a premium. Import and export would cause most companies to fold or move.
All in all a dream which would be an epic fail.
To tell you the truth I don't give a shit.
Not interested in their welfare.
I'm pretty sure the shipping would find alternate routes pretty quickly.
Of course it would take a team of accountants six months to sort everything out... But on the macro it would appear that they are draining from us more than they are contributing. Hey maybe they could form an alliance with China and drain the living crap out of the Beijing coffers for a change.
Jo