According to etymonline.com, capital comes from “Latin capitalis ‘of the head’”. Capitol comes from “Latin Capitolium, [the] name of the temple of Jupiter Optimus Maximus, protector of the city, on the Capitoline Hill in ancient Rome”. The American architecture “deliberately evokes Roman republican imagery”. The “relationship of Capitoline to capital is likely but not certain”.

Interesting! Thanks for making me look that up!

Damn, if that’s not what they call the cafeteria in the Supreme Court Building, I’m going to be thoroughly disappointed.