This may be the maximum level of U.S. debt that’s sustainable before interest payments trigger a default crisis that even steep tax hikes can’t fix

The Penn Wharton Budget Model warns that U.S. debt exceeding 210% of GDP could trigger a crisis where even steep tax hikes cannot cover interest payments. Current debt is 100% of GDP, with projections reaching 175% by 2056, and healthcare cost growth could accelerate the threshold. A 15-percentage-point tax hike on labor income is proposed as a solution, but factors like higher interest rates and market instability could worsen risks.