We are running smith cart 3.94.0. Is there a way to restrict shipping so that only orders within the us are allowed? Right now, we have shipping set by weight, and I need that to stay, because it calculates the costs correctly, however, I need it to also be allowed if the address is within the U.S. Is there some way I can do this without upgrading? I really don't wan't to have to go through the upgrade process from 3 to 4, I don't have a half of a day to spend on this. 

If I did upgrade, is there an easier way to do this? I just don't want to have to rely on my regex because if I miss something and an out of country order happens, then my client will be upset.