His first major accomplishment was the passage of the Civil Rights Act of 1964. He assembled more than one hundred votes for the proposed legislation eventually passing it. Also during 1964, he was critical of J. Edgar Hoover's management of the Federal Bureau of investigation. Muskie was upset by its "overzealous surveillance and its director's intemperance". Muskie also sponsored the construction of the Roosevelt Campobello International Park near Franklin Delano Roosevelt's New Brunswick estate. Due to its international nature, Muskie was asked to chair a joint U.S.-Canada commission to maintain the park. In 1965, he was again sponsored the Water Quality Act (later to be known as the Clean Water Act). He was the floor manager for the discussion and led to its passage in 1965 and its successful amendments in 1970.