'Should we negotiate with Communist China?' Is sort of a moot question since we already do. And have been for over forty-years now since the Nixon Administration. And we negotiated with Russia the whole time during the Cold War. Russia, which was a much larger threat than China ever was. At least militarily, but never had the economic strength that the People's Republic of China has today, because the Soviet Union was a total Marxist state, with a complete centralized command and control economy. As the total isolation of the Communist Republic of Cuba showed the least almost sixty-years now, you don't improve Communist states by simply ignoring them.
By America engaging with Russia and Communist states in Eastern Europe during the Cold War proved, was that America was by far a superior society and country. Not a people, but our values and form of government, our freedom, was far superior than anything the Communists could offer their people. We proved that by showing the people in those Communist countries what freedom and democracy were about and why they would want those things for themselves either in America, or back home. Americans, didn't emigrate to Russia during the Cold War for the most part. But Russian and other Slavs in the Soviet Union, as well as Jews, emigrated to America during that period.
So of course America should be negotiating with Communist China, Communist Cuba and Communist Korea, as we did with Communist Russia during the Cold War. Because it simply works, because it allows for people on both sides to see for themselves without government propaganda, the differences between freedom and statism. The quality of life that someone has in a liberal democracy, or even social democracy like in Europe, compared with how they would live in a Marxist state. Where there's no such thing as freedom and individuality. Just a superstate, an obese big government, that is addicted to controlling their own people.