Is authored by one or more justices, and agrees with the outcome decided by the majority, but state other reasons supporting the outcomes

the relevant circumstances of a legal dispute or offense as determined by a trial court. ... a court opinion that results when a majority of justices agree on a decision in a ... the tradition that a U.S. senator from the state in which a federal judicial ... votes with the majority but for different legal reasons than the other justices.

one of the major compromises in the constitutional convention was between the small states and big states. the small states wanted each state to have the same number of representatives in congress. the big states wanted representation based on population.