The US has a lot of clout in the world and exports its laws and culture abroad pretty heavily. Countries that have tried to outlaw Coke or Cigarettes are usually sued into the ground by large US corporations and, when that fails, the US has used sanctions to back up the accessibility of US products.

Basically, America's crazy overreach forces our laws onto other nations - this is actually one thing that really frustrates me about corporate tax loopholes, that overreach could be trivially used to force better international standards for corporate VAT taxes there just isn't the political will (due to lobbying) to get it done.