But that's not comparable. If the tax take/GDP was the same today as it was when the budget was balanced then (19.9%), there would still be a deficit well over a trillion dollars. The US is simply spending a lot more. In terms of entitlements, certain things have changed structurally.

For example in the year 2000, people aged over 65 were 12.4% of the U.S. population. Today, that demographic has grown dramatically to 19% of the population. That's fewer people working and paying taxes while also simultaneously drawing more from medicare and social security.

This doesn't mean it's "impossible". But to balance the budget today without major spending cuts would require raising taxes 39%. It's just so different than it was then to make the math work out.