Donald Trump, a man who doesn’t know when to stop talking, wishes the US military would stop talking about its plans to help retake the ISIS-held city of Mosul.

During Wednesday's debate, Trump said Gens. George Patton and Douglas MacArthur would be "spinning in their grave" over the Pentagon’s public discussions of the ongoing push to reconquer Mosul, which began earlier this week. Trump has refused to answer any questions about his own strategy for fighting ISIS because he says he wants to maintain the element of surprise. On Wednesday, he said the US had tipped its hand too early, giving ISIS time to get key leaders out of the city and bolster its defenses.

"Why can't they do it quietly? Why can't they do the attack, make it a sneak attack, and after the attack is made, inform the American public that we've knocked out the leaders, we've had a tremendous success?" Trump had asked at an earlier debate. "Why do they have to say we're going to be attacking Mosul within the next four to six weeks?"

On its face, it seems like a reasonable question. The wars we see in movies and on TV tend to involve well-trained troops swooping in at night to overrun enemies who had no idea they were coming. They don’t tend to involve PowerPoint presentations with maps of the areas that will be hit and a rough chronology of how the attack will unfold.

Dig a little deeper, though, and it becomes clear that Trump is wrong on two counts. First, there are legitimate military and political reasons why operations as big as the coming Mosul fight can't be prepared in complete silence. And second, ISIS isn't stupid, and the US hasn't said anything publicly that the group didn't already know.

"An ISIS that didn’t know there’d be an attempt to retake Mosul would be an ISIS that was too stupid to have taken Mosul in the first place," said Stephen Biddle, a professor of political science and international relations at George Washington University. "If ISIS wasn’t already preparing, they’d be guilty of military negligence, and we would be delighted that they’re so incompetent."

Or as Michael Knights of the Washington Institute for Near East Policy put it, "There’s no sneaking up on the other side’s capital. We didn’t sneak up on Berlin in World War II, and we’re not going to do a surprise attack on Mosul either."

The war over the war for Mosul

Trump isn’t the first to accuse the Pentagon of giving away the store.

In February 2015, an unnamed officer from US Central Command, which oversees the war against ISIS, told reporters that the offensive to retake Mosul would begin that April or May and include up to 25,000 Iraqi and Kurdish security forces.

The level of detail — which included the directions the Kurds would attack from and the Pentagon’s plan to use former Mosul police officers in the fight — surprised reporters and prompted Sens. John McCain and Lindsey Graham to allege that Centcom had "knowingly briefed our own war plans to our enemies" and put US and Iraqi lives at risk.

The briefing also infuriated senior Iraqi officials, who hadn’t been notified in advance that the US planned to share so much. Iraqi Defense Minister Khaled al-Obeidi said at the time that Baghdad, not Washington, would decide when the assault began. "A military official should not reveal the timing of the offensive," Obeidi said.

A lot has changed since then, however. Backed by US airpower and military aid, Iraqi and Kurdish forces have rooted ISIS from its former strongholds in Ramadi and Fallujah and moved steadily closer to Mosul. The US estimates that ISIS has lost 47 percent of the territory it once held in Iraq.

On the ground, meanwhile, tens of thousands of Iraqi troops, Kurdish peshmerga, and Sunni tribal fighters are massing outside Mosul in advance of the attack.

That takes us to a broader point: Preparing to launch a massive military operation to retake Iraq’s second-largest city is not the kind of thing that can be done stealthily. It’s literally not possible to move tens of thousands of troops, heavy artillery, and other equipment to the outskirts of the city a couple of hours before the attack is supposed to begin.

Making matters even harder, the 20,000 to 30,000 troops that will take part in the offensive aren’t part of a central, unified command. Moving fighters from so many different groups — some members of a formal army, some just tribal fighters with minimal training — and all of their weapons and equipment into place around a city as big as Mosul takes a while. And the idea that all that activity would go unnoticed by ISIS fighters in Mosul and the surrounding areas beggars belief.

So even if the Obama administration hadn’t announced that it planned to retake Mosul soon, ISIS would still have known. They’re terrorists, not blind.

And indeed, the US buildup hasn’t gone unnoticed by ISIS, which has spent months fortifying its positions inside Mosul. That’s the other reason Trump is wrong to worry about the US losing the element of surprise. Washington never had it in the first place.

ISIS is already preparing for war — and has been for a long time

It’s been two years since Mosul fell to ISIS, which means that ISIS has had two years to stockpile weapons and build up an extensive network of defensive fortifications. Among them, according to CNN: oil-filled moats ringing the outskirts of the city that can "be set ablaze to obscure the vision of coalition air power."

Other news reports indicate that ISIS is building walls and trenches to make it harder for ground troops to enter Mosul while also digging tunnels so its fighters will be able to wage a guerrilla war inside the densely populated city.

Senior ISIS leaders, meanwhile, have already either fled Mosul or gone into hiding because of the unrelenting US effort to track and kill them from the air. The head of ISIS, Abu Bakr al-Baghdadi, gave a triumphant public address after capturing the city in 2014. He hasn’t been seen in Mosul since.

"The idea that Baghdadi would have been hanging out in a cafe in Mosul drinking coffee if we hadn’t telegraphed that we’re coming is just silly," Biddle said.

And that, in a nutshell, is the single biggest problem with Trump’s argument.

There are aspects of the coming Mosul offensive that would without question do real damage if made public. ISIS would benefit from knowing the exact day the offensive will begin, the roads coalition troops will take into Mosul, the radio frequencies they’ll use to communicate, the buildings they plan to target, and other details about how the US and its allies hope to conquer the city.

The US hasn't disclosed any of those things. The Pentagon has hinted that the offensive would begin at the end of October or in early November, given a very broad estimate of the number of troops that will take part, and made the obvious points that the Kurds stationed north of the city would attack from the north while the Iraqi and tribal forces operating south of Mosul would move up from the south. It's hard to imagine the US getting more specific as the fighting draws nearer.

"On a daily basis, we’re using tactical surprise very effectively to kill ISIS leaders," Knights said. "When a basic guided bomb drops out of the air, they get no warning whatsoever. So we’re hardly excessively telegraphing many of the aspects of the campaign."

There’s good reason to talk about invading Mosul before the fighting starts

Announcing that a major military operation to kick ISIS out of one of its most important strongholds is just around the corner also has clear public relations value.

The anti-ISIS coalition runs the gamut from independence-minded Kurds to Sunni tribal fighters wary of what they see as a pro-Iranian government in Baghdad. Keeping them on the same page is easier when there’s tangible progress to point to — and when they can be told that the climactic battle for Mosul is imminent.

Talking up the offensive also offers a morale boost for the civilians trapped inside the city, since they’re now effectively being told, "Hold on a little longer — help is on the way."

Indeed, the US-led coalition has dropped fliers over the city promising the people there that they have not been forgotten and that they will be liberated for this same reason.

And, finally, it serves to counteract ISIS propaganda. ISIS’s Arabic motto translates to "enduring and expanding," and much of its appeal and legitimacy derives from its success on the battlefield and its control of a large swath of territory in Iraq and Syria that it claims is the caliphate reborn.

Defeating the group on the battlefield is hard, but counteracting its propaganda is even harder. That’s what makes the battle for Mosul so important. Taking back the city would deal ISIS a body blow militarily while also making its messages of strength and power ring hollow. And that’s something that would definitely be worth talking about.