The constitution - or rather, judicial interpretation of the constitution - is constantly in flux. The kinda things that were seen as constitutionally valid by SCOTUS less than a century ago are completely off the wall compared to today. And today's views will likely be very different from a future court's interpretation.
It's in flux because it's really difficult for us to change the constitution. So, we basically live patch the constitution with the supreme court.
A proper fix would let the constitution change over time.