Social Security is now the federal government's largest, and probably its most popular, program. It has performed well and grown hugely over the twentieth century, with the trust fund that pays benefits generally being kept financially solvent and paying people a decent return on their contributions.
But all of that could change, with the slowdown in fertility, longer life expectancies, and slower economic growth expected for the twenty-first century. Now it looks as though a continuation of the present system will entail progressively higher payroll tax rates and progressively lower rates...