Federal debt is an odd beast, quite unlike any personal or corporate debt. Unlike every other debtor, the national debtor (i.e. the US government) also has the power to create money (via the Fed, usually) and also the power to set interest rates. And a lot of federal debt is actually owed to the debtor (yes, the federal government loans itself money). Furthermore, the debtor lives in perpetuity and can thus rollover repayment in perpetuity, as long as the interest payments to debt holders is made. And unlike private or corporate debtors, the federal government has the power to legally raise more money in order to make its payments.