The California Supreme Court upheld a ban on same-sex marriage Tuesday, ratifying a decision made by voters last year. The ruling comes at a time when several state governments have moved in the opposite direction.

The court’s decision does, however, preserve the 18,000 same-sex marriages performed between the justices’ ruling last May that same-sex marriage was constitutionally protected and voters’ passage in November of Proposition 8, which banned it.

The court’s opinion, written by Chief Justice Ronald M. George for a 6-to-1 majority, noted that same-sex couples still had a right to civil unions. Such unions, the opinion said, gives those couples the ability to “choose one’s life partner and enter with that person into a committed, officially recognized and protected family relationship that enjoys all of the constitutionally based incidents of marriage.”

Justice George wrote that Proposition 8 did not “entirely repeal or abrogate” the right to such a protected relationship. Instead, he said, it “carves out a narrow and limited exception to these state constitutional rights, reserving the official designation of the term ‘marriage’ for the union of opposite-sex couples as a matter of state constitutional law.”