In many states support is around ~50%. So opposition to same sex marriage isn't a fringe opinion in a lot of places in the USA. Even in liberal California 33% still don't support it.
It's not fringe yet, but it is extremely well on the way to being a minority opinion. It already is when you consider the national scope.
The states where a majority are still opposed are all states nobody wants to live in for a variety of reasons including poor educational standards and lack of economic development.
There might be some relations between these facts. Maybe not. But it is interesting, isn't it? That those are the places where these opinions stick around the longest?