Senator Ball became the sixth incumbent U.S. Senator to lose reelection joining Democrat James Shields in 1859, Democrat Charles Towne in 1901, Republican Moses Clapp in 1916, Republican Frank Kellogg in 1922, and Republican Henrik Shipstead in 1946.
Humphrey was a resident of Minneapolis, former political science professor at Macalester College (1943-1944), radio news commentator, and Mayor of Minnneapolis (1945-1948). He would later serve as Vice President (1965-1969).
Dunne was a resident of Minneapolis, Farmer-Labor candidate for the 5th CD in 1928, Workers Communist nominee for U.S. Senate in 1928, Socialist nominee for Secretary of State in 1936, and the Socialist Workers nominee for U.S. Senate in 1952, and 1954. Dunne was nominated by petition.