There was at least one beating with a cane related to a speech about US slavery that happened in the senate building, if not while the senate was in session.
Yes, the caning of Charles Sumner by Preston Brooks. It was because there was such a heated rift between the north and the south that representative Brooks thought it would be more fitting to discipline his opponent with a cane used to beat an unruly dog than to challenge him to a duel, as was the norm at that time. He beat Sumner repeatedly with the cane, then calmly walked away like a total gangsta - definitely one of the most memorable stories from my high school history class.
It's worth noting that not too long after that incident, there was a civil war...
It's worth noting that not too long after that incident, there was a civil war...