Dear President Xi and President Obama,
You will both have received many public and private letters of advice prior to your meeting on Friday and Saturday in California. They will urge you to take up specific issues ranging from military and trade concerns to human rights. That diversity of concern is an indicator of how complex the relationships between your two countries are. They lend themselves to no easy solutions, and it is doubtful there will be immediate, radical change when you and your teams conclude the talks.