WWII and taxes

The Revenue Act of 1942 . . . permanently revolutionized the American tax system. . . . Despite the alleged fiscal promiscuity of the New Deal, to all but a plutocratic few Americans the prewar federal tax system was an utter irrelevancy, or at most a decidedly minor nuisance. All that now changed, forever. By lowering the personal exemption to $624, the 1942 law immediately brought thirteen million new taxpayers into the system.

David M. Kennedy, Freedom from Fear: The American People in Depression and War, 1929-1945 (New York: Oxford Univ. Press, 1999), ch. 18