Since Senators have been directly elected in 1913, most reelection attempts are successful in Massachusetts. That's true around the country as well. A full 90% of Senators seeking reelection were successful this past November.
Here at home, only one Democrat, Senator David I. Walsh has been defeated in a reelection attempt, though on two separate occasions. I’ve been thinking of Walsh while ruminating over a data point in the recent poll that finds only 44 % of voters think Senator Elizabeth Warren “deserves reelection.”