The 1971-1972 opening between the United States and China would not have come about without the secret talks between U.S. National Security Advisor Henry Kissinger and Chinese Premier Zhou Enlai that established some common policy objectives and eventually culminated in the Nixon-Mao summit. As Donald Trump and Kim Jong Un prepare for their June 12 meeting in Singapore, there are three crucial lessons they can learn from past summits, such as Richard Nixon and Mao Zedong’s encounter in the early 1970s and the Ronald Reagan-Mikhail Gorbachev summits of the late 1980s: They will need to establish common policy ground, manage their respective domestic politics, and forge trusting and respectful personal relationships.