The first thing to understand is that the U.S. government does not have to ever run a surplus in order to pay back its debt. Debt service is included in the budget; running budgets that are merely balanced is enough.<p>The second thing to understand is that the U.S. government is the financier of last resort, and thus, has nowhere to store surpluses other than itself. That is why the Social Security trust fund is invested in U.S. Treasury bonds...nothing is more trustworthy. Thus we find the perverse result that government surpluses actually create more government debt! So not only is a balanced budget sufficient, it is the optimum.<p>So the U.S. government's only option to finance capital investments is debt. In the startup world you can find an angel or VC to infuse you with cash in return for equity; but the U.S. government's equity offering is already fully subscribed (it belongs to the citizens). So the government's only option for unplanned expenditures is to issue debt.<p>From this we can see that it is expected that U.S. budgets will habitually miss low. Debt acculumates because it is the best way for the government to manage its finances. The amount of debt, and its rate of growth, matters only in the context of what the U.S. economy is doing.<p>When a company experiences a sales slump, they can dip into capital to maintain operations until sales improve. When the U.S. economy hits a slump, we only have debt--so debt has gone up. This is an expected result, not a crisis. We just have to make sure the rate of debt growth falls under GDP growth as part of the recovery.