This year, payment of interest on that debt is estimated at $225 billion, Gordon said. He and Riedl point to Congressional Budget Office projections indicating that without any change in spending, interest on the national debt will hit $1.1 trillion a year by 2021.
At that point, it will exceed what the country will be spending on national defense.
“By 2025, revenue will be able to finance only interest payments, Medicare, Medicaid and Social Security. Every other federal government activity — from national defense and homeland security to transportation and energy — will have to be paid for with borrowed money.”