The option that Treasury considered "least harmful" was to delay payments until it had sufficient revenue on hand to pay them.

Here's what that could like this time around.

Say Treasury starts facing cash shortfalls on Friday, Feb. 15, and the ceiling hasn't been raised. The bills due that day -- an estimated $52 billion -- wouldn't get paid until Feb. 22, by which point enough revenue had come in to cover them, according to Center estimates.

The $16 billion in bills due the next business day -- Tuesday, Feb. 19 -- wouldn't be paid until Feb. 25.

Those kinds of delays would snowball as Treasury came up against more days when large payments are due.