Question: The 1988 United States Senate election in Montana took place on November 8, 1988, which incumbent United States Senator, ran for re-election in 1988, American politician of the Democratic Party who represented Montana as a member of the United States House of Representatives from 1969 to 1977, and as a United States Senator from 1977 until 1989?

Context articles: United States Senate election in Montana, 1976
United States Senate election in Montana, 1966
United States Senate election in Montana, 1928
United States Senate election in Montana, 1964
United States Senate election in Montana, 1942
John Melcher
United States Senate election in Montana, 1960
United States Senate election in Montana, 1954
United States Senate election in Montana, 1936
United States Senate election in Montana, 1988

The 1976 United States Senate election in Montana took place on November 2, 1976.
 Rather than seek a fifth term, incumbent United States Senator Mike Mansfield, a Democrat, opted to retire, creating an open seat.
 United States Congressman John Melcher, who had represented Montana's 2nd congressional district from 1969 to 1977, won the Democratic nomination and defeated Stanley C. Burger, the Republican nominee, by a wide margin in the general election.
The 1960 United States Senate election in Montana took place on November 8, 1966.
 Incumbent United States Senator Lee Metcalf, who was first elected to the Senate in 1960, ran for re-election.
 He won the Democratic primary uncontested, and moved on to the general election, where he was opposed by Tim M. Babcock, the Republican nominee and the Governor of Montana.
 Though the race remained close, Metcalf was able to expand on his 1960 margin of victory, and defeated Babcock to win a second term.
The 1928 United States Senate election in Montana took place on November 6, 1928.
 Incumbent United States Senator Burton K. Wheeler, who was first elected to the Senate in 1922, ran for re-election.
 After successfully defeating several challengers in the Democratic primary, Wheeler advanced to the general election, where he faced Republican nominee Joseph M. Dixon, the former Governor of Montana who had previously served in the United States Senate from 1907 to 1913.
 Though the election was closer than Wheeler's first election, he still managed to defeat Dixon to win his second term in the Senate.
The 1964 United States Senate election in Montana took place on November 3, 1964.
 Incumbent United States Senator Mike Mansfield, who was first elected to the Senate in 1952 and was re-elected in 1958, ran for re-election.
 Mansfield won the Democratic primary in a landslide, and advanced to the general election, where he faced Alex Blewett, the Majority Leader of the Montana House of Representatives and the Republican nominee.
 Though Mansfield's margin was significantly reduced from 1958, he still overwhelmingly defeated Blewett and won his third term in the Senate.
The 1942 United States Senate election in Montana took place on November 3, 1942.
 Incumbent United States Senator James E. Murray, who was first elected to the Senate in a special election in 1934 and was re-elected in 1936, ran for re-election.
 Following his victory in a competitive Democratic primary, Murray advanced to the general election, where he was opposed by former United States Attorney for the District of Montana Wellington D. Rankin, the Republican nominee and brother of representative Jeannette Rankin.
 In a closely fought election, Murray narrowly defeated Rankin to win re-election to his third term and his second full term in the Senate.
John Melcher (born September 6, 1924) is an American politician of the Democratic Party who represented Montana as a member of the United States House of Representatives from 1969 to 1977 and as a United States Senator from 1977 until 1989.
The 1960 United States Senate election in Montana took place on November 8, 1960.
 Incumbent United States Senator James E. Murray, who was first elected to the Senate in a special election in 1934 and was re-elected in 1936, 1942, and 1948, and 1954, declined to seek re-election, creating an open seat.
 United States Congressman Lee Metcalf won out in a crowded Democratic primary and faced off against former United States Congressman Orvin B. Fjare, who won in a similarly-crowded Republican primary.
 Following a close general election, Metcalf narrowly defeated Fjare to win his first term in the Senate.
The 1954 United States Senate election in Montana took place on November 2, 1954.
 Incumbent United States Senator James E. Murray, who was first elected to the Senate in a special election in 1934 and was re-elected in 1936, 1942, and 1948, ran for re-election.
 After winning the Democratic primary against trivial opponents, he advanced to the general election, where he was opposed by Wesley A. D'Ewart, the Republican nominee and the United States Congressman from Montana's 2nd congressional district.
 A contentious and close election ensued, but ultimately, Murray was able to narrowly win re-election over D'Ewart to a final term in the Senate.
The 1930 United States Senate election in Montana took place on November 3, 1936.
 Incumbent United States Senator James E. Murray, who was first elected to the Senate in a special election in 1934, ran for re-election.
 He narrowly emerged from a competitive and close Democratic primary, wherein he was challenged by United States Congressman Joseph P. Monaghan, who represented Montana's 1st congressional district.
 In the general election, Murray was opposed by Thomas O. Larson, a State Senator and the Republican nominee, and Monaghan, who, after losing the primary, ran as an independent candidate.
 Murray ended up winning a second term, and his first full term, in a landslide, defeating both of his opponents by a comfortable margin.
The 1988 United States Senate election in Montana took place on November 8, 1988.
 Incumbent United States Senator John Melcher, who was first elected to the Senate in 1976 and was re-elected in 1982, ran for re-election.
 After winning the Democratic primary, he faced Yellowstone County Commissioner Conrad Burns in the general election, and a grueling campaign followed.
 Ultimately, Melcher was narrowly defeated in his bid for re-election by Burns.