Yellen warns of 'calamity' unless Congress raises the debt limit. What's the holdup?

The U.S. government could default on its debt in a matter of weeks if it doesn't raise the debt ceiling.

That would spell "economic calamity," Treasury Secretary Janet Yellen warned this weekend.

"Whether it's defaulting on interest payments that are due on the debt or payments due for Social Security recipients or to Medicare providers, we would simply not have enough cash to meet all of our obligations," she told . "And it's widely agreed that