Nguyen represents a legislative district two hours north of Phoenix that includes the city of Prescott, the same district that Finchem represents and where he was cited on a recent Saturday by an officer who said he was driving 48 mph (77 kph) in a 30 mph (48 kph) zone.
In the U.S., 43 state constitutions offer protection to lawmakers for speech and debate, and about 45 provide legislative immunity from arrest related to legislative service.
Immunity generally falls into two categories, one protecting speech and debate and the other protecting lawmakers from arrest, according to the nonpartisan National Conference of State Legislatures.
While it's unclear how many times legislative immunity has been invoked since it was written into the Arizona Constitution in 1912, Finchem is far from the first to claim it.
That's because the Arizona Constitution shields state lawmakers from any civil process and arrest for anything but treason, felony and breach of peace during legeslative sessions and the 15 days before.
