Working-class has traditionally been a big Democratic Party base, yes. (And I'm only a Democrat inasmuch as I disagree with the vast majority of Republican Party stances) Policy-wise, Democrats are still the pro-union, pro-minimum wage raising, pro worker's rights party, but a) they have gone drastically off-message and failed to convey it, b) they ran Hillary Clinton, who voters didn't believe was really "for the people", c) they have chased donors just as much as Republicans (although Dems are trying to fix the money in politics issue, and Republicans really aren't), which has pushed them away from the working class, and d) allowed the Right-wing media to successfully portray them as coastal elitists.