The new Obama adminstration is in the midst of a deep economic trouble and it cannot afford to take any step that can affect the economic situation. That could be the reason why US chose not to speak of any human rights violation by China or Tibet issue during Hillary Clinton visit to China. Instead she was speaking of the need for China to continue investing in US treasuries, for mutual good. Incidentally, China has become the largest investing country beating Japan by a comfortable margin, in US treasuries. It is holding over 500 billion worth of US treasuries as on date and sharp downturn could be in the offing anyway, due to local Chinese growth issues.