Actually, they don't 'finance' anything in a fully-fiat regime...
...because fiat can ESSENTIALLY be printed without limit.
The only real limit (Ludwig von Mises called it the 'Crack-Up Boom') is when the Rubes figure out they've been HAD. Whereupon they know that the 'currency' they have will NEVER be worth as much again, and decide to DUMP it as fast as possible. Hyperinflation is the inevitable result.
What stops it? Nothing - ultimately. BUT - what delays it?
Taxes, for two basic reasons:
1) They have to use fiat to pay them.
More importantly,
2) They keep a LID on the inevitable inflation, by draining the excess that would otherwise reveal the scam sooner, rather than later. THAT is their real "enforcement" function.
Picture a bathtub with the water left on. Taxes are the 'drain.' It will inevitably overflow because the rate coming IN (money printing) exceeds the drain letting it out. The drain just keeps the tap flowing a while longer.
And if the drain is too big - the tub empties, and we call that "deflationary Depression." Either way, it's eventually over. (I describe the end as either "fire or ice.") A balance allows the scam to go as long as it has, but interest on created fiat forces the tap to have to open wider. (And the "Magic Money Machines" DOGE discovered are just printing without even being recorded on the balance sheets, or charging interest on the new crap - totally inflationary.)
