War bonds are voluntary. "Be a patriot" is psychological pressure. The real "last resort" is what comes after that: forced draft, forced taxes - in extreme cases fake unwithdrawable currency like in the 3rd reich. It can get worse.

Winning a war can be expensive, but losing a war is devastating. The money of a country that just lost a war is worth nothing.

Not only that, after the war its population is subject to the will of powers that still hate them and dont have their best onterest in mind.

Germans to this day cant organize, cant study or discuss their own history, they cant even depict some symbols in art and games or they can face jail time.

I'm not defending the nazi regime, just using Germany as an example that losing a war can have consequences far worse than just losing money.