Congresspeople have immunity for anything they say on the House floor barring treason. Mike Gravel read Ellsburg's Pentagon Papers into the Congressional Record in the '70s.
> Congresspeople have immunity for anything they say on the House floor barring treason.
This is true all up until the "barring treason" part, which is incorrect.
Congresspeople have immunity for anything they say on the floor, additionally, they can't be arrested while attending a session except on charges of treason, felony, or "breach of peace". [1]
A lot of people in recent discussions on HN have been confusing the exception that allows them to be arrested on certain basis while they are attending session as an exception to the immunity for legislative acts.