“We’ve never gotten to the point where the United States government has operated without the ability to borrow,” Lew said. “It’s very dangerous. It’s reckless, because the reality is, there are no good choices if we run out of borrowing capacity and we run out of cash.”

Lew said the government has been managing to make payments since May by shifting money around, but it will run out of those options on October 17. Unless Congress votes to raise the debt ceiling, the federal government will be left with “a very, very short window of time” before it would have to stop cutting checks for Social Security recipients or disabled veterans and would undermine the full faith and credit of the U.S. government, he said.