As relations between the United States and China sour, there is one important constituency keen on maintaining close trade ties — small American companies across all 50 states, many of which have done business with China for decades and hope to be doing so decades from now.  Owners and managers of such businesses — none of them Fortune 500, or even 50,000 — fret that no one in authority is trying to resolve the many areas of disagreement between the two countries, from the trade wa