What did Donald Trump do today?

He attacked the USPS.

Trump today threatened to withhold pandemic-related funding for the United States Postal Service, which will run out of money in September, unless it agreed to quadruple its prices for shipping packages. He called the USPS a "joke" and accused it of giving special treatment to Amazon, which is owned by Jeff Bezos. Trump hates Bezos, who is much wealthier and who owns the Washington Post.

The Post Office's finances have been precarious for years, but mostly because of a 2006 law requiring it to fund its pensions 75 years in advance. It is otherwise profitable.

As economists pointed out, forcing the Post Office to quadruple its prices—making it totally uncompetitive with private companies like FedEx and UPS—would simply let those companies raise their prices as well. 

It also wouldn't accomplish Trump's main goal of hurting Bezos, since Amazon would simply pass those shipping charges along to customers. (This is also what happened with Trump's tariffs on China and other countries.)

But chaos with the mail might help Trump shut down mail-in voting plans being drafted in many states. Trump has said publicly that increasing ballot access to registered voters through mail-in voting would hurt his chances of being re-elected. 

Of course, Trump can't actually afford to let the USPS shut down, or even to force it to jack up its rates—which would hurt small businesses and the Americans who receive mail deliveries far more than it would Jeff Bezos. But other than lashing out at Amazon, Trump did not offer any explanation for why he thought quadrupling shipping costs was necessary.

How is this a bad thing?

• Major functions of government shouldn't be threatened by the president's personal grudges.