Benton McMillin (September 11, 1845 – January 8, 1933) was an American politician and diplomat.
He served as Governor of Tennessee from 1899 to 1903, and represented Tennessee's 4th district in the United States House of Representatives from 1879 to 1899.
He served as a diplomat during the administration of President Woodrow Wilson, initially as Minister to Peru (1913–1919), and afterward as Minister to Guatemala (1920–1921).Known as the "Democratic War Horse" for his persistent campaigning on behalf of the Democratic Party, McMillin served as an elector in fourteen presidential elections from 1876 to 1932, and attended nearly every Democratic National Convention during this period.
As governor, he signed anti-child labor legislation and standardized the state's school textbooks.
His attempts to create a federal income tax as a congressman led to the landmark Supreme Court decision, Pollock v.
Farmers' Loan & Trust Co.
(1895), which declared federal income taxes unconstitutional.