Frankel is a mainstream economist, so I doubt he has much of an idea about US debt, either.

Interest payments, which account for 13% of total spending, cannot be cut either – unless the US wants to default on the national debt.

The United States can pay any debt it has because we can always print money to do that. — Alan Greenspan, 13th chairman of the Federal Reserve

The US doesn’t need austerity, it needs to tax the wealthy. But it doesn’t need to tax them in order to pay for stuff, because it has money in infinite supply. It needs to tax the wealthy to reign in the power of the wealthy and to lessen wealth inequality. But it probably isn’t going to, because the wealthy run the country, and they always have.