It’s the oblique route for sure, but could be just as effective in the long run. You wouldn’t have to actually overturn the legal concept of gay marriage, while at the same time being able to prevent gay marriage from happening in the future.

You just have to empower the position with the power to deny access to a marriage license and then fill those positions with people who don’t think it should exist. With one ruling you could potentially make it legal to deny gay people marriages, deny women the right to a divorce, or whatever insanely bigoted shit religious people dream up.