> The case, Moore v. U.S., involves a unique provision of the 2017 Tax Cuts and Jobs Act, which imposed a one-time retroactive tax applicable to individual U.S. shareholders of foreign corporations. Under previous law, U.S. taxpayers had to pay taxes on overseas corporate income when that income was repatriated to the U.S. in the form of dividends. The 2017 act abolished the tax on overseas income, bringing the U.S. tax system into line with those of most other developed countries. But it also created a “mandatory repatriation tax” on the corporation’s undistributed income since 1986, payable not by the corporation but its shareholders.