Caleb Boggs won reelection to a second term over Democratic candidate James M. Tunnell Jr., whose father had served in the Senate in the 1940s. Georgia Democratic incumbent Richard Russell Jr. was reelected unopposed to a sixth full term (and seventh overall.) Idaho Republican incumbent Leonard B. Jordan won reelection a full term, having previously served out the unexpired term of the late Henry Dworshak. He defeated Democratic Congressman Ralph R. Harding. Illinois Incumbent Democrat Paul Douglas, seeking a fourth term in the United States Senate, faced off against Republican Charles H. Percy, a businessman and the 1964 Republican nominee for Governor of Illinois. Also running was Robert Sabonjian (I), Mayor of Waukegan. A competitive election ensued, featuring campaign appearances by former Vice-President Richard M. Nixon on behalf of Percy. Ultimately, Percy ended up defeating Senator Douglas by a fairly wide margin, allowing him to win what would be the first of three terms in the Senate. Iowa Republican incumbent Jack Miller was reelected to a second term, defeating Democrat Elbert B. Smith, who had previously run for the state's other Senate seat in 1962. Kansas Incumbent Republican James B. Pearson won reelection to a full term, having previously served out the unexpired term of Andrew Frank Schoeppel following Schoeppel's death. He defeated Democratic Congressman James Floyd Breeding. Kentucky Republican incumbent John Sherman Cooper won reelection over Democrat John Y. Brown Sr., an attorney and former Congressman. Louisiana Incumbent Democrat Allen J. Ellender was elected unopposed to a sixth term. Maine Republican incumbent Margaret Chase Smith won reelection to a fourth term over Democrat Elmer H. Violette, a state legislator and future judge of the Maine Supreme Judicial Court. Massachusetts Republican State Attorney General Edward Brooke defeated his challengers. Republican incumbent, Leverett Saltonstall, was retiring after serving for 22 years. Brooke was the first black U.S. senator elected since Reconstruction. Michigan Republican incumbent Robert P. Griffin won reelection to a full term, having initially been appointed to the seat following the death of Patrick V. McNamara six months earlier. He defeated Democratic former Governor G. Mennen Williams. Minnesota Incumbent Democratic U.S. senator Walter Mondale, who had originally been appointed in 1964 to replace Hubert Humphrey after Humphrey was elected Vice President of the United States, defeated Republican challenger Robert A. Forsythe, to win a full term. Mississippi Incumbent James Eastland, who first entered the Senate in 1941, faced the opposition