Of all the father-son relationships in Star Trek: The Next Generation that political differences had separated them once again.
Interestingly, Star Trek: Picard season 2. However, they all made peace with their absent or difficult fathers, but Spock didn't get the chance.
Sarek & Spock’s Lifelong Father-Son Issues Explained
Initially, the issues between Sarek and Spock were rooted in family tradition. Sarek had expected Spock to follow in the footsteps of ing the Vulcan Expeditionary Group like he and his father before had done. Spock had instead elected to Starfleet Academy, causing a rift between father and son that would take almost two decades to fix. Star Trek: Discovery later revealed that one of the reasons for Sarek's anger at Spock's decision was that he had been forced to choose between Michael or Spock for a place on the Expeditionary Group. Sarek's decision was rendered meaningless by Spock enrolling in Starfleet.
When Sarek became ill during the events of "Journey to Babel," Spock saved his father's life with a successful blood transfusion. After this, their relationship improved, although Sarek did not apologize for his opposition to Spock ing Starfleet until much later. After Spock's death in Star Trek II: The Wrath of Khan, Sarek sought out iral James T. Kirk (William Shatner) to request retrieve Spock's body from the Genesis planet. After Spock's resurrection, Sarek finally apologized for his objections, realizing that Spock had surrounded himself with people of good character.
Later, it was Sarek who advised Spock to pave the way for peace between the Klingons and the Federation, eventually opening the door for Klingon Worf (Michael Dorn) to Starfleet in TNG. Sadly, Spock and Sarek's paths diverged once more in the period between the events of Star Trek VI: The Undiscovered Country and TNG season 5, episode 7, "Unification I". Picard sought out Sarek to investigate Spock's possible defection to the Romulan Empire. While there, a dying Sarek tells Picard that he and his son publicly disagreed over how the Federation handled the Cardassian border war, causing another father-son rift.
Why Sarek Was Close To Michael Burnham In Discovery, Not Spock
In TNG's "Unification Part II" it's revealed that Spock and his father never shared a mind meld, which is surprising to Picard. Star Trek: Discovery later reveals that Michael Burnham shared something with Spock's father that was described by Sarek as "more than a mind meld". This is because, following a fatal bombing of the Vulcan Learning Center during Michael's childhood, Sarek used his "katra" - the Vulcan soul - to bring Burnham back to life. Prior to Spock's death in The Wrath of Khan, Dr. Leonard McCoy (DeForest Kelly) had received Spock's katra, which proved vital in locating him on the Genesis planet.
Like McCoy with Spock, Burnham retained part of Sarek's katra, which ed for their closeness in Discovery seasons 1 and 2. The katra became a way for Michael and Sarek to seek each other out, such as when Discovery rescued Sarek from an assassination attempt by logic extremists. Michael regularly sought advice from Sarek, such as in the Discovery premiere when she asks for his guidance on dealing with the Klingons. Where Spock had rejected his father's teachings, Michael's katra connection and her respect for her adoptive father Sarek meant that the two maintained a far closer relationship.
Sarek & Spock Never Settled Their Issues In TNG
Sarek died during Spock's TNG Vulcan-Romulan unification mission, so he never got a chance to reconcile his differences with Spock. The Cardassian border war was an incredibly controversial period in Federation history, so it's understandable that such a hot political topic would drive a wedge between the two Vulcan ambassadors. It's interesting that, after he receives his father's apology for their estrangement, Spock pursues a diplomatic career like his father. It's a tacit suggestion that, as a son, he's made his peace with his father's expectations and has realized he no longer has to rebel against living up to Sarek's example.
Due to an earlier mind meld with Sarek, Picard gained insight into how he felt about his son, Spock. The revelations of Star Trek: Picard season 2 suggest that the complex relationship between Spock and Sarek resonated with Jean-Luc. To help with Spock's grief at losing his father, Picard mind-melded with him, and shared the feelings of love and iration that Sarek had for his son, feelings he could not express as an emotionally repressed Vulcan. Although Sarek never got to fully reconcile with Spock, at least he can rest in the knowledge that, at the very end of Spock's Star Trek timeline, he knew how his father felt about him.