system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 how Supreme Court justices decide who writes for the majority and minority, and which opinion(s) ultimately comprise the precedent for later cases.
gpt
If the Chief Justice is in the majority, he decides who writes the majority opinion; otherwise, the justice who's been there the longest decides who writes it. Dissents aren't really restricted; anyone can write a dissent if they want, because there's no requirement that all the justices who disagree sign off on the same dissent.

It's only the majority opinion that sets the precedent.