Paradoxically, the very moments when charisma becomes most attractive are often the moments when its risks are greatest.

In the summer of 2017, Nina Jankowicz, a twenty-eight-year-old American, was working in Kyiv as a communications adviser to Ukraine’s foreign ministry as part of a yearlong Fulbright fellowship.

Prime Minister Justin Trudeau announced Monday that in addition to banning single-use plastics, his government would take other, unspecified steps to reduce plastic pollution. Trudeau did not specify ...