America cooperated with the Soviets to fight smallpox. Why is it so hard for the US to work with China against Covid-19?

• Since the 1960s, when the US overcame Cold War differences with the Soviet Union to defeat smallpox, America has taken an illiberal, ethno-nationalistic turn
• These dark undercurrents, stirred up by Trump, have made it harder for the US to set aside its differences and cooperate with China