Congress has long directed the government to spend more money than it collects in taxes. That means the government has to borrow money to meets its obligations, which it does by selling Treasury securities.
Treasury securities are a promise from the government that you if give it money now, it will pay you back with interest later. They have long been considered among the safest investments in the world.
But now, the U.S. is flirting with not paying its bills by refusing to increase the amount of money that the government is legally allowed to borrow — its "debt ceiling."
We explain the basics of how the system works and what the consequences might be if the ceiling is not raised and the government runs out of money.