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- The trajectory of US debt interest payments is not sustainable, Maya MacGuineas told Insider.
- Interest will eclipse defense spending in four years, the Committee for a Responsible Federal Budget president said.
- By 2051, interest payments will be the single largest federal expenditure, topping Social Security.
US debt this past week hit an all-time high of $33 trillion amid a ballooning federal deficit and a massive wave of Treasury bills.