The same way Americans pay for their weapons production for more than 50 years since they last defaulted on their reserve currency on 1971.

If you haven't heard, the efforts to abandon USD as reserve currency are accelerating since Russian sovereign funds were stolen in the West and Trump started the trade war.

That's why central banks are buying so much gold again.

Nothing prevents the EURO from becoming the next reserve currency, since Bretton Woods agreement on USD as reserve currency was scrapped in 1971.

Laws against deficit spending in EU can just as easily be suspended because of "national emergency", " Putin, Russia... " et cetera.