This is a must read (1.6MB PDF): Debt Limit Analysis
Also, August Invoices Show U.S. Treasury’s Limited Choices
The U.S. government, whose legal authority to borrow money expires on or about Aug. 2, expects to take in $172.4 billion next month — enough to cover little more than half of its bills due then, according to a study for the Bipartisan Policy Center, a research organization.
The U.S. may not have to default on outstanding debts or withhold interest payments for that month; it may be able to cover $29 billion in anticipated interest due on Treasury securities with its cash receipts.
This is just the first day after the money well runs dry:
This could get rather ugly if that debt ceiling isn't re-negotiated.