By the 1920s, many states had adopted income taxes on individuals and corporations.Hellerstein, pp. 429, 431. Many of the state taxes were simply based on the federal definitions. The states generally taxed residents on all of their income, including income earned in other states, as well as income of nonresidents earned in the state. This led to a long line of Supreme Court cases limiting the ability of states to tax income of nonresidents.
By the 1920s many states had adopted income taxes on individuals and corporationsHellerstein pp 429 431 Many of the state taxes were simply based on the federal definitions The states generally taxed residents on all of their income including income earned in other states as well as income of nonresidents earned in the state This led to a long line of Supreme Court cases limiting the ability of states to tax income of nonresidents