Why Do We Have A Debt Ceiling?

Treasury secretary Timothy Geithner is warning that without raising the debt ceiling "we risk catastrophic damage to the American economy." Meanwhile, Republican Senator Jim DeMint rejects that assessment, saying, "we've got enough tax revenue to pay our bills. It's not ideal, but we don't need to panic."

So what is the debt ceiling exactly? Why do we have one to begin with? And how can national leaders have such different perspectives on it, from "risking another great depression" to "not a big deal"?

Washington Post reporter Lori Montgomery says the debt ceiling was started in 1917 to give the Treasury more freedom to borrow money, and there's very little known about what would happen if there was a default.

"No one actually knows what would happen, because it's only happened once before in a limited way [during]... a brief technical default in the 1970s," she told Here & Now's Robin Young.