What did Donald Trump do today?

He accidentally told the truth about his tariffs.

In what appears to have been meant as a defense of his trade policies, Trump tweeted today that "Billions of dollars are, and will be, coming into United States coffers because of Tariffs."

This is correct. What Trump didn't mention--and may not even understand--is that those "billions of dollars" are being paid by American consumers.

A tariff is a tax on an imported good. Overseas manufacturers pay those taxes up front, and then recoup those costs by raising prices. 

One of two things then happens. If the tariff "works," it makes the imported product too expensive compared to domestic versions, and American consumers pay a higher price than they normally would (but no taxes are collected). If the higher prices fail to dissuade American consumers, they pay an even higher price, and some of it becomes tax revenue.

Meanwhile, retaliatory tariffs cause the exact same process in reverse. Trump is essentially--but accurately--bragging that he has raised taxes worldwide.

Those retaliatory tariffs have badly hurt American farmers, who exported soybeans and pork (among other products) to China. This forced Trump to use a now-obscure Depression-era program to spend tends of billions of dollars in order to prop up those markets. Among the beneficiaries of this corporate welfare are Chinese companies operating in the United States. In other words, Trump is using taxes paid by American consumers to protect Chinese companies from the consequences of his tariffs against China.

What is the problem here?

• It should be possible to hear the truth about a president's tax policies without it being an accident.

• A president who doesn't know or can't remember what a tariff isn't competent to hold office.