"Law governing removal of a sitting Congress(m/w)/Senator?"

By The US Oath of Office… [U.S. Constitution, Article VI, clause 3]

… Constitutional Framing

Delegate James Wilson of Pennsylvania viewed oaths as “left handed security only” and that “a good government did not need them and a bad one could not or ought not to be supported.”

Not completely sure what part(s) Q is referring to and which will be used to remove members… my guess all parts of them, just different for each [member(s)]

https://history.house.gov/Institution/Origins-Development/Oath-of-Office/