I recently posted a piece in which Ross Douthat argues that the social justice movement is becoming not a faction of liberalism, but an entirely distinct ideology whose values are not entirely consistent with liberalism in its typical sense. Here he comes at that question from a different angle, looking at past movements with similar values and commitments.
[The political power of the social justice movement], once claimed, could be used the way the old Mainline used its power: not to replace liberal political forms but to infuse them with a specific set of moral commitments and to establish the terms on which important cultural debates are held and settled. Who should have sex with whom, and under what conditions and constraints? Which religious ideas should be favored, and which dismissed with prejudice? What conceptions of the country’s past should be promoted? Which visions of the good life taught in schools? What titles or pronouns should respectable people use? Just as the old denominations once answered these questions for Americans, their post-Protestant heirs aspire to answer them today.
If they succeed where the religious right failed, it will be because post-Protestantism enjoys an intimate relationship with the American establishment rather than representing an insurgency of outsider groups, because centrist failures and Trumpian moral squalor removed rivals from its path, and because its moral message is better suited to what younger Americans already believe.