Trivia Tuesday: Playing with Politics

This actor won a special election to the United States Senate in 1994 and was reelected for a full term in 1996. He did not run for reelection in 2002. A Republican, he represented his home state from December 2, 1994 - January 3, 2003.

When he joined the cast of "Law & Order" in the fall of 2002, He became the first serving U.S. Senator to take a regular TV acting job. His term did not end until January 2003.

He is the only actor to be a regular on two different "Law & Order" series at the same time. From March to May 2005, he was on both "Law & Order" and "Law & Order: Trial by Jury."

He also plays the same character as a recurring guest star in "Law & Order:Special Victims Unit." Richard Anderson, Marla Gibbs and David Hasselhoff are among the few other actors to have played the same regular character on two different series simultaneously.

He is one of four cast members from "Law & Order" whose character became a regular on a "Law & Order" spin-off.

Along with Jerry Orbach, Jesse L. Martin and Leslie Hendrix, he is one of only four actors to play the same character on all four "Law & Order" series ("Law & Order" (1990), "Law &Order: Special Victims Unit" (1999), "Law & Order: Criminal Intent" (2001)and "Law & Order: Trial by Jury" (2005)).

In 1977, in real life, he took on the case of a home state parole board chairman under suspicious circumstances. His work helped to expose a cash-for-clemency scheme that ultimately toppled the governor of his home state. The scandal became the subject of a best-selling book and later a film, “Marie,” in which he portrayed himself, becoming one of the very few professional actors to portray himself. (I, personally, can't name any myself)

Who is he?

Bonus Questions: What state did he represent in the Senate? What character does he play in "Law & Order?"