I think that if the present political discussion of open borders happened a couple of decades ago, a well known economist, Milton Friedman, would have been on the open borders side with the dems; but not for the same reason. To Friedman, unimpeded immigration would destroy all that the "Great Society" had become; as he was quoted as saying: "It's just obvious you can't have free immigration and a welfare state."
If Friedman were alive now, I'm not so sure he would believe that the present stoopid dems wouldn't try to have both along with medicaid for all. For Bernie Sanders' baby to be implemented, a Mercatus Center study suggests that essentially that federal revenues would have to double to cover the $32.6 Trillion over a decade cost of the program assuming that doctors, hospitals and drug companies will accept lower payments. I guess that it'll be open season on everyone with a job and that Tina Turner will get several new neighbors. https://apnews.com/09e06d686a1a481fa76e3fd91f3fcbc2