Class politics are on the rise. Insurgent teachers have brought the word “strike” back into the political lexicon, and Bernie Sanders is attracting millions with his jeremiads against the “billionaire class.” Some liberals, however, insist that there is nothing new to see here — that “class politics is just another form of identity politics.”

The writer Jill Filipovic recently laid out this stance in a series of tweets, arguing “‘Working class’ is an identity. ‘Worker’ is an identity . . . None of these are neutral, universal defaults. Running on them is also identity politics.”

Filipovic’s argument, directed against “red rose twitter,” has obvious roots in the split between Sanders supporters and the rest of the Democratic Party. In the 2016 primary, Hillary Clinton sought to undermine Sanders’s claim to represent the left of the party by attacking him for supposedly ignoring issues of race and gender oppression. As she put it in one infamous sound bite,