When was the last time a Democrat won the White House without someone from a slave state of the mid-19th century on it? Massachusetts/Vermont doesn’t express a whole lot of geographical diversity, and doesn’t put any new states in play.
Obama/Biden
Clinton/Gore
Carter/Mondale
LBJ/Humphrey
JFK/LBJ
Truman/Barkley
FDR/Truman
FDR/Wallace (1940)
Didn’t know Rhode Island was a slave state. Very interesting.