> The US's leaning on the Supreme Court to make social progress is really a result of its inability to make social progress in sane ways through legislatures.
The situation with slavery and segregation in the United States is unique (and unique legal mechanisms were created to combat the issues). But it's not clear to me that you can generalize from that to other social issues. On homosexuality, for example, the U.S. is between Western Europe and Eastern Europe, and similar to Italy in terms of acceptance. Absent the Supreme Court, many U.S. states would have same-sex marriage in similar time-frames to EU countries.
As to abortion, public opinion mirrors the actual laws in countries like France and Germany: support for making it legal up to 12 weeks, subject to things like waiting periods, with strong support for making it legal after that with only limited exceptions.
Sure, some U.S. states would be stragglers, but the same is true in the EU. Ireland didn't legalize abortion until just a couple of years ago. Switzerland and Poland still don't have same-sex marriage. How would the EU react to the European Court of Human Rights taking these decisions away from the state legislatures? Maybe that's what should happen, but this thread is about polarization. It would be polarizing as hell.