The united states financed its efforts in world war ii by

US funded its World War II effort massively by raising taxes and tapping into Americans' personal savings.

Explanation:

During World War II, the United States began to provide significant military supplies and other assistance to the Allies in September 1940, even though the United States did not enter the war until December 1941

The US paid for the Great War the same way States always pay for war: It stole the money from its citizens through taxation and public debt. By the time the US entered the Great War, the personal income tax was already in place ... And then another war came along, with more taxes and more war bonds. Fleece, waste, repeat.

War bonds