hristov didn't really answer your question. I'll try...I am not a lawyer, but have paid tons of money to them over the years ;).
Bottom line is if you sell the product in the U.S., you can be sued by a U.S. patent holder. If you absolutely know you are infringing before you go into the U.S. market, I don't know what to tell you. If you do not know your infringing or there are any number of patents, like so many software ones, that are so encompassing you may be, then your in the same boat with just about anyone else writing software, so go ahead and take your chances.
As to your second question, "if not necessarily me then someone in the distribution chain", I have no idea which party can be held liable and to what degree.
Bottom line is if you sell the product in the U.S., you can be sued by a U.S. patent holder. If you absolutely know you are infringing before you go into the U.S. market, I don't know what to tell you. If you do not know your infringing or there are any number of patents, like so many software ones, that are so encompassing you may be, then your in the same boat with just about anyone else writing software, so go ahead and take your chances.
As to your second question, "if not necessarily me then someone in the distribution chain", I have no idea which party can be held liable and to what degree.