Douthat: When Immigration Stalls

Dammit, this is exactly the kind of thing I've been worrying about for a couple of years now.
Add to it that the progressive left intelligentsia is now pushing an anti-assimilation position as a matter of principle...and, well, I worry that we're playing with fire. Anti-assimilationism is just a consequence of certain versions of multiculturalism--so nothing about that should surprise anyone. Multiculturalism was pushed onto society in the early '90's without anything much resembling a justification, and now its more extreme consequences are being similarly pushed. This is, of course, the M.O. of the PC left. Asking permission at every "stage" of sex was a joke, a straw that helped break the camel's back, in the '90's. It became a quasi-law at all public universities in the 'teens...
   As Douthat notes...it could be fine. But if it isn't fine, it could be a disaster. And I have no idea how to calculate the odds of those two possibilities. Seriously, this is nothing to screw around with. We'll always want immigration. But it seems like assimilation rates (to whatever extent such a thing is measurable) provide an objective way to determine when it's happening too fast / we've got too much of it.