A year after the United States entered the Second World War the federal government needed additional revenues to pay for the war effort. Congress had given away much of the government's usual means of financing itself, printing its own money, when it created the Federal Reserve in 1913. A voluntary income tax had been in place for 29 years, but for Constitutional reasons, fewer than 11 percent of Americans had to pay the income tax at that time. As a result, Congress enacted into law the Victory Tax Act of 1942, which included concurrent law for automatic wage withholding. The Victory Tax was a direct tax on income. However Article 1, Section 2, Clause 3 of the U.S. Constitution requires that direct taxes be apportioned to the several states, not citizens directly, and therefore it was unconstitutional. The government attempted to legitimize these new laws by citing Article 1, Section 5, Clause 2 of the Constitution: "To support Armies but no apportionment for money to that use shall be a longer term than 2 years."
The new legislation gave Henry Morgenthau, then Secretary of the Treasury, two voluntary income taxes to which he needed the voluntary compliance of US citizens. In December 1942, Morgenthau came up with a brilliant idea to encourage Americans to volunteer to pay by making the income tax a patriotic duty. To help implement this idea, Morgenthau ordered John J. Sullivan, a Treasury Department official, to contact Walt Disney.
The irony of all this is that Disney got stiffed by the US Government for all those training films they made during WW2.