But, yes, the US has an unfortunate tendency, since the War of Independence, and the Civil War, continued to the present, of always fighting wars off budget.
That's not even remotely true.
The US has, for most of its history, levied taxes for the explicit purpose of paying for wars.
The Federal Government didn't exist during the Revolution, so the individual states raised taxes.
I'm not going to get into the nitty gritty of pre-20th century war taxes, because they were on things like slaves, carriages, sugar, and whiskey.
Just remember, every dollar you spend for something you don't need, is a dollar spent to help the Axis
To pay for the Korean War, Congress heaped taxes on top of the already high WWII rates.
President Johnson cut domestic spending and created surtaxes specifically to pay for Vietnam.
AFAIK, George W. Bush was the first President to categorically refuse to raise any taxes to pay for his wars.