Udall served in the House of Representatives for 30 years, and frequently challenged the leadership of both parties. He was a strong liberal in the western tradition, with a particular interest in environmental issues. He was a pioneer opponent of the tobacco industry and as early as 1963 proposed legislation that could have put cigarette manufacturers under the control of the Federal Food and Drug Administration.
He was a leading campaigner for reform of election finance laws and drafted and led the campaign for the Federal Election Campaign Act of 1971. He was also in favour of a national health insurance system.
"Mo" Udall was a rugged westerner who looked the part - he was 6ft 5in tall - and came from rugged western Mormon stock. His great-grandfather led the first Mormons out of Utah into what was then the Arizona territory. His father, Levi Udall, started out digging ditches, became a successful farmer, qualified as a lawyer, and served for years on the Arizona Supreme Court, ending up as the state's chief justice.
Mo was one of five children of Levi and Louise Udall. His mother published a book about the life of a Hopi Indian woman. His older brother Stew served in Congress, then resigned to be President John F. Kennedy's secretary of the interior.
When Mo was five years old his eye was injured by a boy he was playing with. At that time his father could not afford proper medical care, so he was taken to a country doctor who was "mostly drunk" and treated the eye with poultices. The eye became infected and was eventually lost.
In spite of his handicap, Udall volunteered for the army air force, where he reached the rank of captain and served in the South Pacific. It wasn't until he got into the army that he got the first decent glass eye he had had; unlike its primitive predecessors, it matched the colour of his good eye.
He commanded an all-black unit in Louisiana for two years, an experience that, he later said, "really shaped my life". Fighting his men's battles against the routine discriminations of the Deep South in those days, coming on top of his own personal handicap, turned him into a quiet but very determined, even radical fighter for a fairer society.
After leaving the army he went to the University of Arizona, where he was elected president of the student body and, in spite of the loss of one eye, played intercollegiate basketball. Later he played briefly as a professional for the Denver Nuggets, before going to law school and setting up as a lawyer in Tucson in partnership with his brother Stewart.
Udall became a congressman in a special election called after his brother joined the Kennedy Administration. As soon as he arrived in Washington he disclosed his personal finances, something most unusual at the time, and he campaigned for greater transparency and for reform of the law on campaign finance. The reforms incorporated in the 1971 Federal Election Campaign Act, of which he was a major sponsor, played an important part in exposing the Nixon administration's casual attitude to campaign finance and thus led to the Watergate scandal.
In 1967 Udall refused to vote for the unseating of the black congressman Adam Clayton Powell, accused of financial impropriety, on the grounds that it would constitute an injustice to his Harlem constituents. He also expressed "a deep-seated and conscientious disagreement" with his own Mormon church over its segregationist policies towards black people.
In the 1970s he also campaigned against "strip mining", unregulated open- cast mining, and although his bill was twice vetoed by President Gerald Ford, it passed in 1977, saving millions of acres of land. And in the 1980s, already a sick man, he led the campaign against drilling for oil in the Arctic National Wildlife Refuge in Alaska.
Twice in the 1970s Udall campaigned to be Speaker of the House of Representatives, and again to be majority leader, the number two leadership position, but in each case without success. He was however a genuinely serious candidate for the Democratic presidential nomination in 1976, even though he later wrote a book about his experience called Too Funny to Be President (1988).
He was in fact a very funny man, with a dry western sense of humour and a nice ability to make jokes against himself. He was much in demand in Washington as an after-dinner speaker. When already seriously ill with Parkinson's disease he compared that horrible condition to a woman called Paula Parkinson who was starring in a contemporary sex-and-lobbying scandal: "They both keep you up at night," he quipped, "and they both give you the shakes."
The last years of his life were rather terrible. He spent them in a Veterans Administration hospital in Washington DC, much of the time unconscious. One of his children, Mark Udall, has just been elected to the House of Representatives from Colorado, as has a nephew, Tom Udall of New Mexico.
Morris King Udall, politician: born St Johns, Arizona 15 June 1922; member, US House of Representatives 1961-91; married 1949 Patricia Emery (three sons, three daughters; marriage dissolved 1966), 1968 Ella Royston (died 1988), 1989 Norma Gilbert; died Washington DC 12 December 1998.Reuse content