Question for Saul re international exposure

I have reviewed many of your posts and don’t see the answer to my question I am about to pose to you, so please forgive me if it is on this board somewhere.

Question: my understanding is that there is a lot of opportunity (or could be) in investing in stocks in countries other than the good old US of A. I know you don’t typically invest in Chinese stocks, and I believe I know the reasons for that, but do you, as a rule, stay away from all stocks other than US companies? And, if so, why?