The income tax was established in 1913 with the ratification of the single sentence of the 16th amendment. Tax rules and regulations have undergone many revisions and changes in the 110 years since then, including the 2017 Tax Cut and Jobs Act. One provision of that act, concerning multinational corporations repatriating income, is being challenged in the case Moore v. United States. Oral arguments in that case, which could have far-reaching implications for the tax system, will be heard by the Supreme Court in December. Dan Shaviro of the New York University School of Law, explains the evolution of the income tax system over the past half decade and some of the possible consequences of the Moore decision, including huge revenue losses for the government. Dan is the Wayne Perry Professor of Taxation at NYU. His newest book is 'Bonfires of the American Dream in American Rhetoric, Literature and Film.'