The chill is felt by all who have built a career on the now-deteriorating Sino-US relationship, including Carla Freeman and her brother.

"The commercial and business relationship has been the thing that's held the US and China together for decades," Charles the son said."But it's seen today as a greater source of tension than alignment."

A little more than 51 years ago, on April 1, 1970, Nixon, in anticipation of a relaxed bilateral relationship, announced the easing of trade controls with China. Between 1979 and 1981, when Freeman acted as the director of Chinese affairs in the State Department, he witnessed Sino-US collaboration in areas from astronomy and geology to education and agriculture."Both Chinese soybeans and sows were of great agricultural and scientific interest to us," he said.

These days, both the diplomat and his daughter are liable to being branded "panda huggers", Carla Freeman said. This is because of the empathy they feel toward China either as a diplomat or as an academic trying to present "Chinese perspectives unadulterated by normative interpretation", to quote the daughter.