Bernie Sanders was ranting about the Republicans taking away Social Security. He is the one who takes it away by immigration. As well as Medicare, Medicaid, and mental health funds.
Without immigration, the marginal in society are still of use to employers. So they have to help them be better employees not just fire them.
When the marginal have jobs, they get married. Then their spouse helps them.
As a married couple they go to church. The minister helps them be better people as do their fellow congregationalists.
Thus the marginal are recycled when the inflow of immigration is zero.
This was the golden era from the 1924 immigration restriction act to the 1965 immigration explosion act.
Bernie Sanders is playing a part. Bernie Sanders shrieks in pain for Social Security cuts as he strikes Social Security, Medicare and Medicaid with third world immigration and takes the good jobs and engineering education with H-1b and Asian immigration.