Volodymyr Zelenskyy has won public adoration for his ability to motivate not only Ukrainians but people around the world. He might be the best version of a 21st-century political leader we’ve seen.

In many ways, Zelenskyy is the most unlikely of heroes. He grew up as a Russian-speaking Ukrainian Jew in the southeastern part of the country. He earned a law degree and pursued a career in standup comedy and acting. Then, quite incredibly, he starred in the comedy series The Servant of the Peop...