The WSJ writes (sub req), "The biggest economic risk of a Donald Trump presidency has always been that his trade obsessions would swamp the benefits of tax reform and deregulation. For two years he has kept his worst protectionist impulses mostly in check, but as he seeks a second term we are now seeing Tariff Man unchained. Where he stops nobody knows, which is bad for the economy and perhaps his own re-election."

Donald Trump's trade war with China has been an overall disaster so far and now he's taking it to our neighbor to the south, Mexico. If only Trump was this caustic, callous and nasty to the world's most murderous dictators instead of our partners. But he saves his recklessness for America's allies.

"The Mexico tariffs also heighten economic uncertainty because they aren’t even about trade. The risk is that Mr. Trump has come to view tariffs as a blunt-force tool to achieve any diplomatic goal. They are Mr. Trump’s magic elixir that will solve any political ailment. Like Barack Obama’s willy-nilly regulation, tariffs can thus pop up at any time for any reason. No supply chain is safe from Tariff Man."

If he could, he would slap tariffs on the Democratic Party in Congress until they bend their knees to all his whims. And as they say, Trump is now blaming Mexico for his immigration problem.

The WSJ makes the point that even after Trump has negotiated a trade deal with foreign countries, he will suddenly change his mind and blow it up. How can any trading partner not be worried that "any trade deal with Mr. Trump is subject to revision on his personal political whim."

The best scenario is that this tariff threat is Mr. Trump’s familiar bluster in which he threatens chaos to get attention and then backs down. But then Tariff Man is impulsive and often his own worst enemy.

No one will ever mistake the Wall Street Journal editorial board as a liberal think tank.