Question: Which American politician who served as United States Senator from 1971 to 1989 was Governor of Florida before Buddy MacKay?

Context:
Buddy MacKay
Kenneth Hood "Buddy" MacKay Jr. (born March 22, 1933) is an American politician and diplomat from Florida.
 A Democrat, he was briefly the 42nd Governor of Florida following the death of Lawton Chiles on December 12, 1998.
 During his long public service career he was also state legislator, U.S. Representative, lieutenant governor and later special envoy of President Bill Clinton's administration for the Americas.
 As of 2017, he is the last Democrat to serve as Florida governor.
John Hoeven
John Henry Hoeven III (born March 13, 1957) is an American politician and the senior United States Senator from North Dakota, in office since 2011.
 A member of the North Dakota Republican Party, he previously served as the 31st Governor of North Dakota from December 2000 to December 2010.
 Hoeven was elected to the U.S. Senate in the November 2, 2010 general election.
 He replaced junior Senator Byron L. Dorgan, who chose not to seek re-election.
 Hoeven became the senior Senator in 2013 after Kent Conrad retired and was replaced by Heidi Heitkamp, who was once Hoeven's opponent for the Governor's office.
Lawton Chiles
Lawton Mainor Chiles Jr. (April 3, 1930 – December 12, 1998) was an American politician from the U.S. state of Florida.
 He served as a United States Senator from 1971 to 1989 and as the 41st Governor of Florida from 1991 to 1998.
Mazie Hirono
Mazie Keiko Hirono ( ; Japanese name: 広野 慶子 "Hirono Keiko"; born November 3, 1947) is an American politician and the junior United States Senator from Hawaii, in office since 2013.
 Hirono, a member of the Democratic Party, previously served as a member of the Hawaii House of Representatives from 1985 to 1995 and as the Lieutenant Governor of Hawaii from 1994 to 2002, serving under Governor Ben Cayetano.
 She was the Democratic nominee for Governor of Hawaii in 2002 but was defeated by Republican Linda Lingle.
 She then served as a member of the United States House of Representatives for Hawaii's 2nd congressional district from 2007 to 2013.
Clifford Hansen
Clifford Peter Hansen (October 16, 1912October 20, 2009) was an American politician from the state of Wyoming.
 A Republican, he served as the 26th Governor of Wyoming (January 7, 1963 – January 2, 1967) and subsequently as a United States Senator (January 3, 1967 – December 31, 1978).
 Earlier, he was the president of the board of trustees of his "alma mater", the University of Wyoming at Laramie in Albany County, then the state's only four-year institution of higher learning.
 He was also a county commissioner in Jackson, the seat of Teton County in far northwestern Wyoming.
 Before his death on October 20, 2009, he was the oldest living former U.S. Senator as well as the third oldest living former U.S. Governor.
George LeMieux
George Stephen LeMieux ( ; born May 21, 1969) is an American politician who was a United States Senator from Florida from 2009 to 2011.
 He is chairman of the Florida-based law firm of Gunster Yoakley & Stewart and was chief of staff to Governor Charlie Crist.
 He was the Deputy Florida Attorney General and is credited with spearheading Crist's successful campaign for governor.
 On August 28, 2009, Crist announced he would appoint LeMieux as U.S. Senator to replace Mel Martínez, who weeks earlier had announced he would resign as soon as Crist announced his successor.
 On April 5, 2011, LeMieux formally announced that he would run against incumbent Democratic Senator Bill Nelson in 2012, but dropped out of the race in June 2012.
J. Howard Edmondson
James Howard Edmondson (September 27, 1925November 17, 1971) was an American politician from the U.S. state of Oklahoma.
 He served as the 16th governor of Oklahoma from 1959 to 1963, and a United States Senator from Oklahoma from 1963 to 1964.
 Elected at the age of 33, Edmondson still remains the youngest governor in the history of the state.
Wendell Ford
Wendell Hampton Ford (September 8, 1924 – January 22, 2015) was an American politician from the Commonwealth of Kentucky.
 He served for twenty-four years in the U.S. Senate and was the 53rd Governor of Kentucky.
 He was the first person to be successively elected lieutenant governor, governor and United States senator in Kentucky history.
 The Senate Democratic whip from 1991 to 1999, he was considered the leader of the state's Democratic Party from his election to governor in 1971 until his retirement from the Senate in 1999.
 At the time of his retirement, he was the longest-serving senator in Kentucky's history, a mark which was then surpassed by Mitch McConnell in 2009.
Samuel Bell
Samuel Bell (February 9, 1770December 23, 1850) was an American politician and lawyer who served as the 14th Governor of New Hampshire from 1819 to 1823, and as the United States Senator for New Hampshire from 1823 to 1835.
 Born in Londonderry in the Province of New Hampshire, Bell became a lawyer in the 1790s, and entered politics by becoming a member of the New Hampshire House of Representatives in 1804.
 In 1806, the year he left the House, he became the head of a bank which during his tenure in that position became the only New Hampshire bank to fail between 1792 and 1840.
 A member of the New Hampshire Senate from 1807 to 1809, and an associate justice of the New Hampshire Supreme Court from 1816 to 1819, Bell was elected to become the Governor of New Hampshire in 1819 as Democratic-Republican.
 Re-elected in 1820, 1821, and 1822 against token opposition, Bell's victory in 1822 was accompanied by the largest share of votes cast for a governor candidate of New Hampshire since John Taylor Gilman's victory in 1795.
 Whilst Governor, New Hampshire's crime level fell, and industry within the state prospered.
 In 1823, declining to stand again for the governorship, he became a Senator for New Hampshire.
 He won re-election in 1829, was the chairman of the United States Senate Committee on Claims, and left the Senate in 1835.
 He retired from public life thereafter, and died in Chester, New Hampshire at the age of 80.
 He is buried in Chester Village Cemetery, Rockingham, New Hampshire.
Bob Kerrey
Joseph Robert Kerrey (born August 27, 1943) is an American politician and lobbyist who served as the 35th Governor of Nebraska from 1983 to 1987 and as a United States Senator from Nebraska from 1989 to 2001.
 Before entering politics, he served in the Vietnam War as a United States Navy SEAL officer and was awarded the Medal of Honor for heroism in combat.
 During the action for which he was awarded the Medal of Honor, he was severely wounded, precluding further naval service.

Answer: Lawton Chiles