Bloomberg Opinion columnist Barry Ritholtz interviews former senator George Mitchell, a leading figure in the Democratic Party who was credited with helping them win back the Senate majority in 1986.Mitchell was elected majority leader in 1989, a position he held until his retirement from the Senate in 1995. He was known among his colleagues in the Senate as an honest leader and skillful legislative strategist. After leaving the Senate, Mitchell was instrumental in negotiating a peace agreement in Northern Ireland and was awarded the Presidential Medal of Freedom.