Something I didn't know is that when the US government ended racial segregation in privately owned businesses they did so not on any sort of human rights or equality basis. Rather they argued that businesses being able to deny black clients service has a depressing effect on the economy, and is thus something the federal government can regulate under the Commerce Clause.
Today there's still people who think that was a bad call not because it ended segregation, but because it gave the government precedent to regulate other things via the Commerce Clause.
1. http://www.radiolab.org/story/radiolab-presents-more-perfect...