the 1972 Massachusetts Senate election, a contest between Incumbent Edward Brooke and Middlesex County District Attorney John J. Droney was the last time that any republican won a full term to the US Senate for the State of Massachusetts.
Edward Brooke, A Stalwart Liberal–yet partisan– Republican, and the first African American elected to the senate since the end of Reconstruction focused his campaign on his incumbency as well as his opposition to the Vietnam war.
By Contrast, John J. Droney ran a strong law and order campaign, supporting Nixon's SCOTUS nominees, aspects of his foreign Policy and even going so far to question the neccessity of the 5th Amendment to the US Constitution
However, Brooke's incumbency and popularity won out convincingly–winning him a final term. After which he would lose reelection in 1978 to Paul Tsongas under a cloud of Scandal.