They’re putting them on Medicare. They’re putting them on Social Security. They’re going to destroy Social Security. This man is going to single-handedly destroy Social Security.” —Trump Undocumented immigrants improve the health of Social Security and Medicare by paying payroll taxes without receiving benefits. In a fact check, we calculated the figure for Social Security payments made by undocumented immigrants is now about $27 billion. For Medicare, it should be at least $6 billion, as the Medicare tax is about 23 percent of the Social Security tax.