 A failure to raise the debt limit will call into question Congress's willingness to meet our obligations that we've already incurred, not new ones, we've already incurred. This is going to undermine the safety of U.S. Treasury securities and will threaten the reserve status of the dollar as the world's currency, the world relies on. American credit rating will be downgraded, interest rates will rise for mortgages, auto loans, credit cards, borrowing.