Not necessarily. If the economy grows faster than recent history, a constant tax rate brings in more revenue.

Also worth looking at the last time the USA completely paid off its government debt.

> On January 8, 1835, president Andrew Jackson paid off the entire national debt, the only time in U.S. history that has been accomplished. [1]

[1] https://en.wikipedia.org/wiki/History_of_the_United_States_p...