Progressives have long imagined that vast riches could be infused into government coffers if only they could tax Americans not just on their income, but on estimates of their total wealth. Treat people as if they'd cashed in all their holdings at today's value and make 'em cough up a share to Uncle Sugar and politicians could just roll in the proceeds. Last month, the Supreme Court threw a lifeline to such dreamers with a decision granting the federal government broad authority to consider money that has yet to be received as taxable income. The idea of a wealth tax lives on, but so do its many flaws.
The opinion in Moore v. United States ventures deep into the weeds of the Tax Cuts and Jobs Act of 2017's Mandatory Repatriation Tax (MRT). The MRT was a one-time tax on the undistributed income of foreign subsidiaries of U.S. corporations, with the bill sent to shareholders.
