(Mandel Ngan/AFP/Getty Images)

“I’m really good at war,” Donald Trump said in 2015. “I love war in a certain way. But only when we win.”

Trump’s belief that the wars we won were good while the wars we lost were bad may have been childish, but you could argue that it made more sense than what many Republicans believe, that pretty much every war is good.

Fourteen months into his term, Trump has not ordered any new invasions, which to some may have come as a surprise. But there are reasons to believe that we could be stumbling toward a military confrontation with Iran.

As we mark the 15th anniversary of the the invasion of Iraq, we should ask what Trump learned from that most disastrous war, and whether it will constrain him in the future. In a few areas Trump’s comments have shown some measure of sanity. But overall there isn’t much reason to feel reassured. Trump, unlike many Republicans, is happy to say the Iraq War was a disaster. But he doesn’t seem to have translated that into broad principles about effective decision-making when it comes to foreign policy challenges.

Back in 2003, President George W. Bush and his administration insisted that we simply had no choice but to launch the war. After all, if we didn’t invade then, Saddam Hussein was sure to attack us with his vast arsenal of terrifying weapons. In its first days, with exciting pictures on the news of the American military rolling over Hussein’s army, there was a feeling of triumph and vindication. All those lily-livered liberals who said it was a bad idea were mocked and shamed, their doubts about America’s ability to remake the world through the use of force proved wrong once and for all.

The costs were staggering: trillions of dollars spent, thousands of Americans killed and tens of thousands wounded in body and mind, hundreds of thousands of Iraqis killed, the rise of the Islamic State and the empowering of Iran. It happened in no small part because of one man’s psychological weaknesses. What led Bush into Iraq was his lethal combination of grandiose ambition and stunning naivete: He believed not only that the war would be quick and easy but also that once Hussein was deposed a wave of liberty would sweep across the Middle East. “We will, in fact, be greeted as liberators,” said Vice President Dick Cheney less than a week before the war began, and in short order the liberation would spread outward to encompass the entire region.

Trump is not a visionary in the same way; he doesn’t seem to give any thought to what might happen beyond next week. But he is uniquely impulsive and uniquely malleable. It isn’t hard to imagine a clever group of aides saying to him, “You know sir, Barack Obama didn’t have the guts to attack Iran,” which could be all it takes to convince him that he ought to.

Doing what Obama didn’t is one of Trump’s most powerful motivations. Last April, Trump ordered the bombing of a near-empty Syrian airfield in response to a chemical weapons attack on civilians by Bashar al-Assad’s government; everyone noted that while Obama had said chemical-weapons use was a “red line,” he backed that line up with negotiations and not force. When Trump launched that raid, he was praised to the heavens for his strong and manly response, unlike his quavering predecessor who was never willing to take such decisive action.

And what happened? Well, nothing. Trump’s bombing run didn’t stop Assad from using chemical weapons again, and the Syrian dictator’s murderous hold on the country has only solidified as he continues to massacre civilians. It was a failure in every way. But do you think that ever crosses Trump’s mind?

We don’t know. Nor do we know whether Trump assimilated other key lessons of Iraq: that invasions inevitably produce results you didn’t anticipate; that undue optimism can be fatal; that military action isn’t going to magically produce the political outcomes you want; or that knocking off one group of terrorists may only give rise to another more extreme group.

If there is one broad lesson Trump seems to have taken, it’s that nation-building should be avoided. “We are not nation-building again,” Trump said last year about Afghanistan. “We are killing terrorists.” But he did so while affirming that we’ll be staying in Afghanistan pretty much forever. So what’s the difference? Moreover, his aversion to nation-building won’t necessarily translate into an aversion to military action. He could be just as ready to let the bombs start falling even if he isn’t willing to mount large-scale occupations.

It’s Trump’s hatred of the Iran nuclear agreement — which he seems to have only the barest understanding of — that could touch off a conflagration. Up until now he’s been constrained by his saner advisers from completely pulling out of the deal, which he regards as a disaster for no evident reason other than the fact that the Obama administration negotiated it. That the deal is doing exactly what it was intended to do — constrain Iran from acquiring nuclear weapons — seems not to have registered. It isn’t hard to imagine a scenario in which we abandon the deal, the other parties are unable to keep it alive, and Iran restarts its nuclear program. That would then be used as justification for military action.

If that day comes, the people around Trump may be egging him on, since the voices of restraint are getting smaller in number. Secretary of State Rex Tillerson will be replaced by the much more hawkish Mike Pompeo. We’ve now heard from multiple reports that national security adviser H.R. McMaster (who wrote an influential book on how a culture of deceit within the government mired us in Vietnam) is on his way out, and one of the front-runners to replace him is former U.N. ambassador John Bolton. Calling Bolton a “hawk” is an absurd understatement; in recent years he has proposed bombing both Iran and North Korea as the best solution to the problems they pose. If he’s hired, he’ll be urging Trump to launch military strikes from the moment he arrives.

That’s not to mention the fact that right now there is an increasingly intense cold war going on in the Middle East between Saudi Arabia and Iran, one in which we’ve taken a clear side. What happens if it becomes a direct conflict? Can we avoid getting sucked in?

I wish I could say that Trump’s few good impulses, like his skepticism about nation-building, offer reason to believe he’ll be able to make wise decisions about future military actions (in between planning self-aggrandizing parades, that is). But it’s awfully hard.