ASPEN — Humans are a tool-making species, but can we control the tools we make? When Robert Oppenheimer and other physicists developed the first nuclear fission weapon in the 1940s, they worried that their invention might destroy humanity.

CAMBRIDGE — During the four decades of the Cold War, the United States had a grand strategy focused on containing the power of the Soviet Union. Yet, by the 1990s, following the Soviet Union’s collapse, America had been deprived of that pole star.

CAMBRIDGE — A century ago, an influenza pandemic killed more people than died in World War I. Today, the COVID-19 pandemic has killed more Americans than died in all US wars since 1945.

CAMBRIDGE — There is no single future until it happens, and any effort to envision geopolitics in the wake of the COVID-19 pandemic must include a range of possible futures.

CAMBRIDGE — US President Donald Trump’s behaviour at the recent G-7 meeting in Biarritz was criticised as careless and disruptive by many observers. Others argued that the press and pundits pay too much attention to Trump’s personal antics, Tweets and political games.