CHENGDU, China In the more than 40 years since China and the U.S. established formal diplomatic relations, accusations have been traded, tensions have risen and fallen and sides have come dangerously close to outright confrontation.

Yet the forced closure of the Chinese consulate in Houston and Chinas order to shutter the U.S. consulate in the southwestern Chinese city of Chengdu mark a new low point in ties between the worlds largest economies that cant be easily smoothed over.