It depends on how you define default.

As long as our government debt is denominated in our own currency there is zero chance of literal default, as we can always print enough money to pay it off. From a practical standpoint, in some ways we have already defaulted, as we have resorted to monetizing the debt by creating new money to buy the new issues. So it kind of depends on how you want to define default. Most would not consider our current situation default, yet at what point of dollar devaluation does it become apparent to all that creating new money is the only method of keeping the Ponzi scheme going?

John