Question: When was the 25th Governor election of Minnesota took place?
Context: Harold Edward Stassen (April 13, 1907 – March 4, 2001) was the 25th Governor of Minnesota.  He was a leading candidate for the Republican nomination for President of the United States in 1948, considered for a time to be the front-runner.  He thereafter regularly continued to run for that and other offices, such that his name became most identified with his status as a perennial candidate. The 2002 United States Senate election in Minnesota took place on November 5, 2002.  Incumbent Democratic U.S. Senator Paul Wellstone was running for re-election to a third term, but died in a plane crash eleven days before the election.  The Democratic-Farmer-Labor Party (DFL) chose former Vice President and 1984 Presidential candidate Walter Mondale to replace Wellstone on the ballot.  Mondale lost to Republican Mayor of Saint Paul Norm Coleman.  The day before the election, Independence Governor Jesse Ventura had appointed Dean Barkley (IP) to serve the rest of Wellstone's term.  As of 2017, this is the last Senate election in Minnesota won by a Republican. The 2008 United States Senate election in Minnesota took place on November 4, 2008.  After a legal battle lasting over eight months, Al Franken from the Democratic-Farmer-Labor Party (DFL) defeated Republican incumbent Norm Coleman in one of the closest elections in the history of the Senate.  Al Franken took his oath of office on July 7, 2009, more than half a year after the beginning of his term on January 3, 2009. Meredith Miles Marmaduke (August 28, 1791 – March 26, 1864) was an American politician who served as the 8th Governor of Missouri in 1844, following the suicide of Governor Thomas Reynolds.  He was also the 6th lieutenant governor and father of John Sappington Marmaduke, a senior officer of the Confederate States Army who commanded cavalry in the Trans-Mississippi Theater of the American Civil War, serving as the 25th Governor of Missouri from 1885 to 1887. The 2012 United States Senate election in Minnesota took place on November 6, 2012, concurrently with the U.S. presidential election as well as other elections to the United States Senate and House of Representatives as well as various state and local elections.  Incumbent Democratic–Farmer–Labor U.S. Senator Amy Klobuchar was re-elected to a second term in a landslide, defeating the Republican nominee, State Representative Kurt Bills by almost one million votes, and carrying all but two of the state's counties. The 1970 Minnesota lieutenant gubernatorial election took place on November 3, 1970.  State Senator Rudy Perpich of the Minnesota Democratic-Farmer-Labor Party defeated Duluth Mayor Ben Boo of the Republican Party of Minnesota.  The 1970 lieutenant gubernatorial election was the final lieutenant gubernatorial election held before the Minnesota Constitution was amended to provide for elections of the Governor and Lieutenant Governor on a joint ticket. The 2006 United States Senate election in Minnesota took place on November 7, 2006.  The incumbent DFL U.S. Senator Mark Dayton decided in February 2005 that he would retire instead of seeking a second term.  The primary elections took place on September 12, 2006.  DFL nominee Amy Klobuchar won the open seat. The 1976 United States Senate election in Minnesota took place on November 2, 1976.  Incumbent Democratic U.S. Senator Hubert Humphrey won re-election to a fifth term. United States gubernatorial elections were held 3 November 1964, concurrently with the presidential election.  Elections were held in 25 states and 1 territory.  This was the last gubernatorial elections for Florida, Massachusetts, Michigan, and Nebraska to take place in a presidential election year.  Florida switched its governor election years to midterm years, while the other three expanded their terms from two to four years, this election also coincided with the Senate and the House elections. The 1940 Minnesota gubernatorial election took place on November 5, 1940.  Republican Party of Minnesota candidate Harold Stassen defeated Farmer–Labor Party challenger Hjalmar Petersen.
Answer: November 5, 1940