The national debt didn’t simply appear one morning at $40 trillion. It is a Frankenstein assembled over generations, with each administration adding pieces and the interest on those pieces continuing to grow long after the president who incurred the debt has left office. This graphic tries to capture that history by assigning new borrowing to the president in office and then allowing the interest attributable to that borrowing to follow it forward through time. It isn’t a claim that presidents single-handedly “caused” these amounts.