The national debt just crossed $39 trillion—almost doubling since Trump vowed to erase it

The United States national debt crossed $39 trillion for the first time Tuesday, arriving at the grim milestone less than five months after it first hit $38 trillion in late October—a pace of accumulation that budget watchdogs and academic economists are now calling, with unusual unanimity, “unsustainable.”​

The milestone, confirmed in Wednesday’s Daily Treasury Statement, lands amid a politically charged moment: it comes roughly two weeks before the ten-year anniversary of President...