20 Things You Didn't Know About Star Trek III: The Search For Spock (1984)
17. Why Did You Leave Him On Genesis?
Mark Lenard's return to Star Trek, though having appeared in The Motion Picture as the Klingon Commander, was something that appeared in Harve Bennet's earliest story ideas for the Search for Spock. In his treatment entitled Return to Genesis, Sarek and Kirk meet early in the film, but on Vulcan, rather than Earth,
Here, we learn that Sarek has been elected Prime Minister of a planet that is wracked with chaos. The news of the Genesis Device has deeply shaken Vulcan, with many young Vulcans fearing the power that Starfleet now wields. As they see it, they are facing galactic Armageddon, and many are revisiting the teachings of the old ways - i.e. the teachings that led to the birth of the Romulan Empire.
The conversation in which the audience learns about the existence of Spock's katra is still present in this version, yet Sarek displays far more hostility and anger toward Kirk. He maintains that as Spock's closest friend, Kirk should have been aware of this.
As the Enterprise leaves for Genesis, Sarek warns them that he may not be in power when they return.