Well, the Boston-area universities and small college towns (Amherst comes to mind) are really liberal/left-wing, and the WASPy towns in MA tend to be really socially liberal (more so than in the past, when they were bastions of Rockefeller Republicanism.
) The working-class Catholics throughout the state are loyal Democrats, except when someone like Reagan or Scott Brown is the candidate. Soi you have many aspects to the Democratic electorate in MA, some more liberal than others-there's a definite class difference in degrees of liberalism.