I find it hard to believe the US negotiators are disappointed. What were they thinking when they tabled the US position? It is so one sided even they can see it. 

They would have known that Mexico and Canada would both say no on all the motherhood issues.

So what is there to be disappointed about? Were they expecting the tooth fairy to make things right? Or was this part of a plan?

This may be a set up to allow RC to pull the plug on NAFTA before the end of negotiations. He simply says Mexico and Canada are not being reasonable (his definition of reasonable) and there is no point beating his head against a brick wall.

Or maybe the US government is in disarray and has no vision for the negotiations, no true objective, no idea what it wants and cannot make up its mind.