It's the beginning of the end for the Union in general. Yeah, people wax on and on about the "Cold Civil War" since Trump, but that wasn't really the case. Even with Trump he basically was all in regarding a strong federal government because he just wanted power. But this decision essentially says that unless a law is in the Constitution, it's meaningless and states can do whatever they want. This will lead to an even greater difference between red and blue states - they're going to look like separate countries. In the end there will be such limited social interaction and legal commonalities between these two geographic regions that the Union will essentially dissolve.