President Trump has changed his mind about Bashar al-Assad. Until Wednesday, it seems he had Syria confused with New Jersey, yet another place ruled by a despot, but now he knows different. Having seen pictures of Syrian children and other civilians killed by an apparent nerve-gas attack, Trump came to grips with reality: Assad is a killer.

But he has ever been thus. Assad had used nerve gas before. In 2013, he killed nearly 1,500 civilians — his own people, by the way — in an attack that almost provoked then-President Barack Obama to take action. A “red line” had been crossed. But after due consideration and an overdose of caution, Obama backed down. Assad was safe. He had to go, Obama declared, but Obama was not going to be the one to make him.

Since then, Assad has continued to dress smart and kill with abandon. His security forces maintain jails where torture is common. His army drops “barrel bombs” on civilians. The extent of the killing, the torture, the attack on doctors and the bombing of hospitals are hard to envision and impossible to accept. Yet this week, both Secretary of State Rex Tillerson, a man of few words and no policies, and U.S. Ambassador to the United Nations Nikki Haley said it was no longer U.S. policy to rid Syria of Assad. A day or so later, Assad apparently used nerve gas.

Trump runs a chaotic White House — Stephen Bannon in, then out. Trump says whatever pops into his head, usually in reaction to something he has seen on Fox News. He has no regard for what he says. A lie, the truth — it is all the same to him. But he has to appreciate that his words matter. In fact, they can kill.

No one can say with any certainty that Assad acted after the Trump administration shrugged indifference to his remaining in office. But it is not illogical to think so. The words of a U.S. president matter and are obsessively examined by foreign governments. They assume that these words mean something. They base policy on them. They sometimes kill on account of them. Vagueness is sometimes useful; it can also be deadly.

On Wednesday, for instance, the president said that Assad has “crossed a lot of lines for me.” What lines is he talking about? Is it the once-momentous red line, which would mean war? Or is it just Trump mouthing off? After all, he has been all over the lot when it comes to Assad. In 2013, he cautioned Obama not to attack Syria: “There is no upside and tremendous downside.” Now, under almost identical circumstances, he is brandishing the red line. Soon, I fear, he will be deflected by something else he has seen on Fox. After all, Bill O’Reilly is in trouble.

We have come to a juncture we all feared. The complications of the world are befuddling Trump. Russia. Syria. North Korea. China. Policies are meandering or nonexistent. Who can persuade Trump to get serious about the presidency? Possibly Jared Kushner, jack of all trades and master of none. Possibly Ivanka Trump, trusted first daughter. Someone has to act. A child sits in the Oval Office. His own children need to discipline him.