President Donald Trump claimed he would eliminate the payroll tax if he is reelected — but an analysis by the Social Security Administration found that such a move would cause the Social Security Trust Fund to run out of money by 2023.

Trump recently signed a memorandum that would temporarily stop the collection of payroll taxes, which is a 12.4% tax split evenly between employees and employers that funds the Social Security and Medicare trust funds. Only Congress can cut taxes, however, so the payroll tax savings would still have to be repaid by next year’s tax deadline — though Trump said he would push to forgive the deferred taxes if he is reelected.