To travel from Washington to Beijing, as I have done in the past week, is to experience an utter contrast in political cultures. Donald Trump’s Washington is a reality television show. Outrageous violations of protocol are essential and the president regularly belittles his predecessors. Xi Jinping’s Beijing is a stately opera. Every word and action is predictable and the president asserts authority by laying claim to the legacy of revered predecessors.

President Xi performed this ritual this week, as he gave a solemn speech in the Great Hall of the People, marking the 40th anniversary of Deng Xiaoping’s policy of reform and openness. Deng’s reforms are worth celebrating. The unpromisingly named Third Plenum of the 11th Central Committee of the Chinese Communist party in 1978 laid the foundations for the transformation of the country. Modern China has achieved levels of prosperity that were unimaginable back then. Central Beijing, thronged with bicycles in 1978, is now clogged with SUVs. Measured by purchasing power, China is now the largest economy in the world.

It is little wonder that Mr Xi portrays himself as Deng’s heir. But the reality is more complex and troubling. The past year has seen domestic and international changes that profoundly threaten Deng’s legacy. And much of that is down to Mr Xi himself.