The Times starts with the obvious: the photos were horrifying, with all that follows from that. Then it moves to the still obvious but all the more alarming.

This time, though, a new American president was seeing the pictures and absorbing the horror.

Donald J. Trump has always taken pride in his readiness to act on instinct, whether in real estate or reality television. On Thursday, an emotional President Trump took the greatest risk of his young presidency, ordering a retaliatory missile strike on Syria for its latest chemical weapons attack. In a dizzying 48 hours, he upended a foreign policy doctrine based on putting America first and avoiding messy conflicts in distant lands.

You don’t want a president who acts on instinct, much less one with built-in readiness to act on instinct, much less one who prides himself on readiness to act on instinct. You don’t. You want one who is well aware that instinct can be wrong and that impulsive military action “on instinct” is a horrific idea – especially in someone who can fire the nukes.

That’s true even if he did 100% the right thing in yesterday’s missile launch.

Mr. Trump’s advisers framed his decision in the dry language of international norms and strategic deterrence. In truth, it was an emotional act by a man suddenly aware that the world’s problems were now his — and that turning away, to him, was not an option.

“I will tell you,” he said to reporters in the White House Rose Garden on Wednesday, “that attack on children yesterday had a big impact on me — big impact. That was a horrible, horrible thing. And I’ve been watching it and seeing it, and it doesn’t get any worse than that.”

Well, it can get worse than that. There can be more victims, just for a start.

But more to the point: this is not the first time. Where was he before? Yapping on Twitter, that’s where.

t was difficult to reconcile the anguished president with the snarky critic of American engagement who, from the comfort of private life, advised President Barack Obama not to strike Syria after a chemical weapons attack in the suburbs of Damascus three years ago.

“President Obama, do not attack Syria,” Mr. Trump said on Twitter in September 2013. “There is no upside and tremendous downside. Save your ‘powder’ for another (and more important) day!”

And it is not easy to square Mr. Trump’s empathy for the victims of a single chemical weapons attack with his refusal to take in thousands of Syrian refugees from years of strife that have turned that country into a charnel house. Relaxing that policy did not come up in the president’s deliberations over striking Syria, his advisers said.

Because that’s not his “instinct” – and that’s one reason “instinct” is not enough, as well as being often the wrong thing entirely.

The president’s advisers insisted his decision was guided by strategic considerations. They were clearly uncomfortable with the suggestion that Mr. Trump was acting impulsively.

Yes, I’m sure they were, but it’s very obvious that he was.

Mr. Trump’s aides described a deliberative process, with meetings of the National Security Council, presentations of military options by the Pentagon and a classified briefing for Mr. Trump held under a tent erected in Mar-a-Lago to secure the communications with Washington. They spoke of phone calls to American allies, consultations with lawmakers and the diplomatic engagement that would follow the Tomahawk cruise missiles.

What is clear, however, is that Mr. Trump reacted viscerally to the images of the death of innocent children in Syria. And that reaction propelled him into a sequence of actions that will change the course of his presidency. Mr. Trump’s improvisational style has sometimes seemed ill suited to the gravity of his office. In this case, it helped lead him to make the gravest decision a commander-in-chief can make.

“I now have responsibility, and I will have that responsibility and carry it very proudly, I will tell you that,” the president said of Syria on Wednesday. “It is now my responsibility.”

I watched him say that last night. I watched it with disgust. It’s not an occasion for him to display his vanity and self-obsession yet again.