Actor Leonard Nimoy, who played Spock in the original “Star Trek” television and movie series, speaks to the residents of the town of Vulcan, Alberta, in this April 23, 2010, file photo. (Todd Korol/Reuters)

Leonard Nimoy, best known for his portrayal of “Star Trek’s” Spock, has died aged 83. “Star Trek” was a highly political show, and Nimoy, through his acting and writing, was at the heart of it.

Spock believed in logic, or what social scientists call rational choice. He tried to set aside emotion in favor of cost-benefit calculations. Decision-making aboard the USS Enterprise would set Spock’s cool reserve in opposition to the fiery passion of his antithesis, the ship’s surgeon Leonard McCoy. Captain James T. Kirk would integrate both reason and emotion and take action. It was a neat way to dramatize the conflicting impulses of human choice.

Nimoy decided early on that to portray Spock as completely free of emotion would be dull. Instead, he figured out that the drama lay in Spock fighting to keep his feelings suppressed, waging a constant war to maintain a cool exterior over a fiery, wounded inner life.

Nimoy wrestled with a duality of his own, fearing that he had become so typecast that he would never escape the shadow of his most famous role. “I don’t go around introducing myself to strangers as Mr. Spock,” Nimoy wrote in his memoir, “But when someone addresses a letter to ‘Mr. Spock, Hollywood, California,’ I’m the one who gets it.”

Fans would come up to him and begin conversations about life as a Vulcan. Nimoy began to conduct imaginary inner dialogues with Spock. “Star Trek’s” creator, Gene Roddenberry, told his biographer that he was “in love with Spock. Though not with Leonard. I know the difference.”

As “Star Trek” grew in popularity through the tumultuous late 1960s and 70s, Nimoy became active in politics. The rationality of the character he portrayed was in demand. Nimoy recalls driving on a highway and seeing a “Spock for President” bumper sticker on the car in front of him. He was a star turn at anti-Vietnam war rallies. “Spock was a character whose time had come,” Nimoy wrote in his memoir. “He represented a practical, reasoning voice in a period of dissension and chaos.”

In the greatest of the “Star Trek” movies, “The Wrath of Khan,” Spock’s utilitarianism is bent toward a profoundly humanistic act of sacrifice. With the Enterprise crippled and trapped and seconds away from annihilation, Spock throws his body upon the ship’s engines to effect repairs, sustaining what he knows to be a fatal dose of radiation so that his shipmates can escape. “The needs of the many outweigh the needs of the few,” he explains. But we know that his act is one of love and friendship rather than cold logic. “He did not feel his sacrifice a vain or empty one,” a grieving Kirk tells the assembled ship’s company at Spock’s funeral. “And we shall not debate his profound wisdom at these proceedings.”

Nimoy had hoped to escape from Spock’s shadow after “The Wrath of Khan,” and insisted on his character’s death being written into the script. Yet the franchise was reinvigorated after this astounding movie, and Nimoy came back to play Spock again.

He made a further major contribution to the political fabric of the show with the sixth movie, “The Undiscovered Country.” In 1990, with the Cold War coming to an end, Nimoy took a walk along a Provincetown beach with Nicholas Meyer, on deck to direct the next “Trek” feature. “Star Trek has always reflected current events,” Nimoy said to Meyer. “What about a story where the [Berlin] wall comes down in space? What is the United States without the Soviet Union? Who am I if I have no enemy to define me?”

“The Undiscovered Country” became a story about the end of a cold war in space, with a massive explosion on the Klingon (read: Soviet) moon of Praxis (read: Chernobyl) prompting a reforming Chancellor Gorkon (read: then-president Mikhail Gorbachev) to sue for peace. Nimoy’s question — “who am I if I have no enemy to define me?” — anticipated the post-Cold War preoccupation of international relations scholars with the issue of identity rather than older questions of material power.

There was more to Nimoy than Spock, of course. Having spent much time with his memoirs, “I am not Spock” and the later mild recantation “I am Spock,” I can attest to the terse force of his prose and the supple imagination of his creative life. Nimoy was an excellent director (his “Star Trek IV: The Voyage Home” was a tonal departure for the series and a mass market blockbuster), and was an acclaimed photographer.

Of course, though, it is as Spock that he looms largest in our consciousness. It seems fitting, then, to give the final line to Spock’s antagonist, McCoy, who knew enough in “The Wrath of Khan” to say this: “He’s really not dead, so long as we remember him.”

Stephen Benedict Dyson is an associate professor of political science at the University of Connecticut and director of UConn’s Humanities House.