2021 Estimated Budget, from CBO (figures in percentage of GDP):
Mandatory Spending: 14%
Discretionary Spending: 6.7%
Net Interest: 3.3%
Deficit: 3.2% ($763billion)
That's the baseline from CBO. That assumes the Bush tax cuts are eliminated in their entirety, and we don't patch the AMT. That's tax revenue that Bill Clinton reached once at the height of the Internet Bubble. That assumes we basically cut all discretionary spending that isn't the military.
And that's still an unsustainable deficit. We need 2.9% at maximum, and preferably something under 1%. The more likely deficit is closer to 6.6% of GDP ($1.573 trillion), and that's still with tax revenue higher than the long-run average.
If you think we can get through this without raising taxes, and raising taxes on damn near everyone, you are probably wrong.