The Real National Debt...

...is not what the government or the people owe to our respective monetary creditors, but what we owe to those who made the ultimate sacrifice to keep us free.  At least two political cartoonists have understood this truth.

From Nate Beeler via All Voices:

From Karl Wimer via Toonpool:

We incur this debt because, as related in a familiar poem, it is the soldier who gives us our freedoms.