The death of Patrick Stewart last week generated an outpouring of grief for one of the greatest actors of our time.

Amid the mourning, there has been another lamentation, for Stewart’s most famous character, Captain Jean-Luc Picard, the commander of the U.S.S. Enterprise on the television series Star Trek : The Next Generation .

TNG , which aired from 1987 to 1994, offered a vision of sincere optimism and hope that today is often met with outright hostility. Picard is an avatar of classic liberalism. He is a champion of egalitarianism, tolerance, and (dare one say it?) diversity.

It was Stewart’s portrayal of Picard that imprinted a vision of enlightened leadership on generations of fans around the world — an ideal that is disappearing from American political life.

Compare Picard with the grubby politicians of our time, with their venal passions, petty tyrannies, and endless narcissism.…