the amount you bring back to the US, duty free, is not dependent upon where you bring it from. Uncle Sam doesnt care if its Belize or Timbuktu - 2 liters per individual is the duty free limit ( might be slightly off on the size - ltrs, qts, 5ths, who cares, 2 big bottles :-), but you get the idea). Of course, for a small fee, you can bring back however much you like!
That said, I've NEVER had my bags checked - worse thing that can happen is they make you pay the duty - no wait - thats the 2nd worst - #1 would be confiscation, highly unlikely though.