Who are the forgotten among us? Are they those whose economic level has declined? Because of the fast digital evolution? Because of changing energy market values (coal vs wind/solar)? Because of the global economy? Assuredly, since FDR, the Democrats have worked steadily to correct such economic inequities. Can it honestly be said that such victims of economic decline have been "forgotten"? There are of course other categories of citizens that bear grudges light or heavy against one another: rurals/citadins, high-school/college educated ones ... . But please show me how "forgotten" applies to them.
As for Socialists, the French voted (1965–88) quite massively for president Françoia Mitterand.