Another reminder of the seriousness of the national debt came earlier this summer, when foreign holdings of U.S. Treasury securities topped $6 trillion for the first time in history.

Any debt carries with it serious challenges. But when the United States owes money to foreign governments, there is the possibility some may use that indebtedness to pressure Washington over diplomatic and military policy. Of the $6 trillion in Treasury securities held by foreign entities, about $4.1 trillion involves other governments.

Expect the amount to continue growing by leaps and bounds unless Washington finds ways to reduce spending. That seems unlikely under President Barack Obama. When he took office, the national debt was just $10.6 trillion. It has skyrocketed to $17.6 trillion. Someone needs to apply the brakes.