The financial crisis of 2008 spurred a big chunk of spending increases and tax cuts to stem the pain of the downturn. That's a key reason why debt held by the public -- individual bondholders, big investors, and foreign governments -- has increased significantly since 2008. That jump will have to be paid off with interest.
Much of those emergency measures will end, so for the next decade annual deficits should be much lower than they've been recently. But over the long run, debt is still projected to grow faster than the economy. Policymakers will have to address it soon, or risk not being able to fund everything Americans expect their government to do.
NEXT: Government spending