The USA is rocketing towards bankruptcy, it's just not sustainable.
That said, what would it mean for the US to go bankrupt?
The US is a sovereign, the sovereign. The country can borrow until the faith and credit in our ability to pay is lost. There's no such thing as bankruptcy, you can default or print money.
The US is rocketing towards depression. Slowing down the velocity of money is the single worst thing you can do for an economy. We're implementing the largest tax increase in history, taking away pensioner benefits, and pushing the cost of healthcare up, nuking consumer demand. There's no adults keeping Trump away from doing stupid shit -- he'll set off an economic death spiral.
Utter insanity.
If our debt and deficits are a revenue problem, they are objectively insoluble.