What caused (or is strongly correlated with) the Democrat swing (relative to 1994) in the 2018 Massachusetts gubernatorial election?
The swing was about 4 percentage points statewide. But it appears to be concentrated in certain areas of the state, like the western area and (to a smaller degree) the more populated east with and including Boston, as the following map from this answer shows.
I am interested in this because I am investigating local/non-federal down ballot races and how polarization impacts them.
What can be reasonably said to have caused Charlie Baker to receive a lower percentage of the vote than Bill Weld? I am also wondering why it is concentrated in those areas and the swing away is concentrated in areas of the state that vote Republican in recent presidential elections.
To be clear, I am not manipulating the data by picking the biggest win in state gubernatorial history. I am simply picking two elections which have similar incumbent candidates.