War Bond
  
Wars are expensive. Those killing machines and soldier training don’t come cheap. During war, governments have, in the past, issued war bonds to help finance operations. Like other bonds, war bonds are debt securities issued by the government.
The difference? They try to guilt-trip citizens into buying them as a favor to the nation since their returns are usually below market rate returns.
For details, see the fine Marvel film, Captain America. His first sojourn after returning from his, uh, experiment, was to go out to the public and market war bonds. Old School.