There is an interesting article I came across on Wikipedia. http://en.wikipedia.org/wiki/United_States_public_debt
The article shows the spiral of the debt over time, beginning at about the time of the last depression. The authors attribute the increasing debt to the spread of federally paid social programs and wars. Of course they also cite several presidents who have done everything in their power to evade paying for the very programs they promoted. That long term irresponsibility is the core issue confronting us today.
What the growing public debt represents, is the will of a series of presidents and congresses that canít resist using what amounts to the national credit card to sometimes solve problems but to mostly buy votes, but who largely refused to take the steps to pay down the debt and instead, made it the problem of the next president/congress.
Roughly 80 years of US history shows that people want the .gov to provide ever more goods and services, but the same people will do everything they can to evade paying for it.
The article is very educational.