What do left-of-center economists have against a tax cut that would raise wages for American workers? They’re always telling us that America needs a raise, and that labor isn’t capturing enough of corporate profits, yet along come Republicans promising to raise wages by encouraging more investment in the U.S., and they react with shock and smears.

That’s the only way to describe the remarkable attack on economist Kevin Hassett for marshaling the considerable economic evidence that cutting the corporate tax rate to 20% from...