The federal government is garnishing Social Security checks to recoup unpaid student debt, leaving thousands of retired or disabled Americans below the poverty line and setting the stage for an even bigger problem, according to a new report. The data from the Government Accountability Office (GAO), compiled at the behest of Sens. Claire McCaskill (D-Mo.) and Elizabeth Warren (D-Mass.), showed that people over the age of 50 are the fastest-growing group with student debt, outpacing younger generations—and compared to younger borrowers, older Americans have 'considerably higher rates of default on federal student loans.' This leaves them open to having up to 15 percent of their benefit payment withheld, in what's called an 'offset.'