The White House’s mixed message on its tariff policy

The laws of economics can be frustratingly inconvenient, especially in Washington. To many lawmakers, the fundamental principles of economics are neither fundamental nor even principles: They are tools to be bent, warped, and manipulated or outright ignored in order to yield up the answers those lawmakers want. 

So it is that Democrats love to argue that raising taxes on things automatically yields more tax revenue for the government. They would have you believe that...