Experts are debating whether legalizing those in the U.S. without permission and encouraging immigration would help shore up the Social Security system with tax contributions — or drain it by adding more beneficiaries to the rolls. Many elderly immigrants contribute to the economy without holding jobs that earn benefits, said Patience Lehrman of Temple’s Project Shine. “A 75-year-old grandmother may not be able to work a 65-hour work week, but by virtue of the fact that they can baby-sit the children of their child who is working full time, their child can participate in the GDP,” she said.