That's not what happened in Casey. A) it didn't involve federal abortion laws. I'm pretty sure it involved PA laws. B) it did not make late term abortion legal. it jettisoned the arbitrary number of weeks standard for a fetal viability standard and it further chipped away at abortion rights by saying that if a law didn't unduly burden the mother's right, then a law could stand. Here is an informative link from PBS that I provide from time to time to clear up Casey for people. https://www.thirteen.org/wnet/supremecourt/rights/landmark_casey.html