I have frequently described Trump’s hostility to Iran as his Iran obsession, but after tonight’s unhinged tweet we might have to start calling it his Iran derangement:

To Iranian President Rouhani: NEVER, EVER THREATEN THE UNITED STATES AGAIN OR YOU WILL SUFFER CONSEQUENCES THE LIKES OF WHICH FEW THROUGHOUT HISTORY HAVE EVER SUFFERED BEFORE. WE ARE NO LONGER A COUNTRY THAT WILL STAND FOR YOUR DEMENTED WORDS OF VIOLENCE & DEATH. BE CAUTIOUS!

— Donald J. Trump (@realDonaldTrump) July 23, 2018

Trump’s approach to international problems is defined by tweeting loudly with threats and insults. Contrary to what his fans think, this does not convey strength. It betrays the extreme weakness of someone who cannot control himself in the slightest. The president has no problem with “demented words of violence” when he is the one making threats against other countries, but he can’t stand it when other leaders issue much milder warnings. This was the Rouhani statement that caused Trump to melt down today:

“Americans should know that peace with Iran is the mother of all peace,” he added. “Likewise a war would be the mother of all wars.”

Note that this is not actually a threat against the U.S. It is a warning not to attack Iran. When U.S. officials make statements like this, we consider it to be part of deterrence. When adversaries say the same thing, fear-mongers try to turn it into proof of the other side’s aggressiveness and evil intentions. Trump’s reaction reminds us that his Iran policy is a very dangerous and hostile one, but the most worrisome thing about this episode is that it shows how quick to escalate tensions the president is. At best, Trump’s response to Rouhani’s comments shows how ready he is to threaten war against another country over nothing more than words, and that by itself greatly increases the likelihood that he might order an attack on Iran over some perceived slight. Trump and his allies have already made sure that tensions with Iran are high and getting worse daily, and the president’s latest outburst will makes things even worse than they were.

Talking about inflicting consequences “the likes of which few throughout history have ever suffered” strongly suggests a willingness to cause massive death and destruction in Iran. It is imperative that Congress make clear that the president has no authority to order an attack on Iran, which would be a flagrant act of aggression, a violation of the U.N. Charter, and a breach of his oath of office.