The belief in the courts and with politicians was that it was settled law and therefore not up for debate. The dems, at least as far as I know, had nothing to do with the case being overturned. It wasn't codified into law for two main reasons - there wouldn't have been enough votes and/or a president wouldn't veto it, and it wasn't seen as necessary given the fact that it was settled law.

Do you have sources for any of this? Because it sounds a little too ridiculous to be truthful