Questions about the Pentagon's credibility carry a host of real-world implications, from allies not trusting America's word, to worries that more troops will commit war crimes, to growing skepticism over intelligence the Pentagon uses to justify military action.

"It's terrible," Eric Edelman, who served as undersecretary of Defense for President George W. Bush, said of the impact Trump is having on the Pentagon’s ability to make its case. "Trump is basically essentially doing things that make the Russians and Chinese happy. They can say, 'They are just like us. They do what's in their interest. The notion that America is different is all bullshit.’”

As the military conflict with Iran deepens, the president's behavior is hamstringing the U.S. military, warned nearly a dozen current and former officials. In particular, Trump's threats to commit violations of international law are fueling perceptions in the Muslim world that the U.S. military is little more than an imperial occupying force.

And the Pentagon’s credibility faces its next big test Wednesday, when senior military leaders brief skeptical lawmakers in the House and Senate on the decision to conduct a drone strike on Iranian general Qassem Soleimani, a move that sparked the missile attack that struck Iraqi bases that house U.S. troops.

Lawmakers, mostly Democrats, have made it clear they’re in no mood to accept the administration’s claims that Soleimani was prepared to attack U.S. forces, especially since there’s no guarantee that the military tit-for-tat in the Middle East will die down anytime soon.

Trump's defenders dismiss claims the president's shoot-from-the-hip style is harming the military's reputation. And the Pentagon says it’s still credible because it doesn’t get political.

“There’s a reason the U.S. Department of Defense remains the most trusted institution in American government — we stay out of politics,” the Pentagon said in a written response to POLITICO. “DoD also maintains a strong relationship with our allies through our [military-to-military] relationships with countries around the globe, where we do joint training, exercises, and serve together on the battlefield.”

But current and former administration officials worry the president's growing pattern of breaking faith with some of those allies, ignoring the chain of command, and forcing Pentagon leaders to publicly defend his actions mean that the military's word does not carry the same weight it once did — just as it tries to head off a major war in the Middle East.

"The institution is losing its credibility because it is continually being politicized, it’s politically being antagonized and it's seen … as a Defense Department that’s either out of touch, that’s rogue, that’s partisan, [or] that’s lawless," said a former senior military officer who served in the Trump administration and requested anonymity to speak freely.

"You don't know what's solid and what's reliable," added a former senior Pentagon official who served in the Trump administration.

The Defense Department’s credibility gap has been on display time and again, most recently this week when a draft letter from a U.S. general to an Iraqi counterpart laying out plans for the withdrawal of troops from Iraq was leaked to the media.

Defense Secretary Mark Esper and Joint Chiefs Chairman Gen. Mark Milley quickly declared the U.S. wasn’t leaving Iraq and said the communication should never have been sent. But it made little difference; Iraq’s prime minister brushed off Esper’s and Milley’s statements and said he was treating the draft letter as official policy.

Even some of the Pentagon's biggest supporters said they don't know what to believe about the episode.

“I do think Esper and Milley have to explain what the hell happened with this unsigned letter that may or may not have gotten sent,” Rep. Mike Gallagher, a Republican from Wisconsin who served as a Marine Corps officer in Iraq, said in an interview. “Was this just pure incompetence or was this part of some deliberate messaging strategy?”

“We can’t be playing games like that, especially at times like this,” Gallagher added, saying he hopes to get clarity from the closed-door briefing Wednesday. “They seemed genuinely surprised. I’m struggling to make sense of it now. I hope they will take advantage of that opportunity ... to tell us what exactly happened.”

Trump seems oblivious to how his words and actions forced Pentagon leaders to constantly scramble to explain away his comments.

Most recently, it was his threat over the weekend to bomb cultural sites if Iran retaliated for the Soleimani attack. If carried out, such an attack would violate both a United Nations-backed treaty calling for the protection of cultural sites in wartime as well as the Geneva Conventions.

After Trump’s comments, Esper hopped into damage control mode. “We will follow the laws of armed conflict,” he insisted to reporters on Tuesday, not directly commenting on the fact that the president had threatened to do something illegal.

Later on Tuesday Trump backed off, telling reporters, "I like to obey the law."

But even some of the most hawkish voices winced at the episode.

"I don't think we should be targeting cultural sites," Gallagher said. "I do think we should avoid anything that would drive a wedge between us and our allies in the region.

"There is no decision more serious and consequential for presidents and commanders in chief than to order military action," added Michael Rubin, a former adviser on Iraq and Iran at the Pentagon from 2002 to 2004 and resident scholar at the conservative American Enterprise Institute. "Trump's off-handed remarks about targeting cultural sites — an illegal order should he try which the Pentagon could never obey — highlights what happens when Trump's political style clashes with the legal and planning processes developed by the Pentagon over decades."

The threat came just weeks after the president took the extraordinary step of granting clemency to a trio of accused or convicted war criminals in the Army and Navy. It set off an outcry in the ranks and on Capitol Hill that Trump was meddling in the military justice system and was encouraging lawlessness and damaging good order and discipline.

After Navy Secretary Richard Spencer was forced out over his handling of Navy Chief Petty Officer Eddie Gallagher’s case, Esper followed Trump’s order and canceled an administrative board that could have removed Gallagher’s SEAL trident pin. In issuing the order, Trump ignored his military advisers in favor of a campaign in conservative media to restore Gallagher’s pin.

"There's a sense of dejection by senior leaders in the Pentagon, that the president and the secretary of Defense are going to side with the loudmouths at Fox News against the reasoned opposition of senior military professionals," a senior Pentagon official with direct knowledge of high-level discussions told POLITICO at the time. "That's the sense in a nutshell."

In another recent example, Trump gave voice to what many critics of U.S. military operations in the Middle East have been saying for decades: It's all about the oil.

After abruptly ordering most U.S. troops out of Syria, the president told reporters that "We're keeping the oil, we have the oil, the oil is secure, we left troops behind only for the oil."

"It can help us because we should be able to take some also," he told reporters on Oct. 27. "And what I intend to do, perhaps, is make a deal with an Exxon Mobil or one of our great companies to go in there and do it properly."

The Pentagon quickly pushed back. “The revenue from this is not going to the U.S.,” Pentagon spokesperson Jonathan Hoffman said, insisting local Kurds will be "the sole beneficiary of the sale of the oil from the facilities they control."

Esper weighed in, saying Trump meant that he wants to keep the oil from benefiting ISIS.

“It's — it's, you know, half dozen, six. I interpret that as deny ISIS access to the oil fields; secure them so that they are denied access to the oil fields,” he told reporters on Oct. 31.

The Pentagon and State Department have long sought to combat the public perception that the U.S.-led invasion of Iraq in 2003 was designed to seize Mideast oil.

The former Trump Pentagon official said the president's statements about the oil is particularly damaging to the Pentagon’s credibility at home and abroad.

"It's is a pretty serious concern among the senior uniformed military," said the former official, who declined to be identified discussing recent conversations with former colleagues. “The taking of the oil fields is exactly what the criticism was of almost every one of our activities in Middle East. It plays right into critics and skeptics and even conspiracy theorists and is against U.S. values.”

The oil field controversy sprang up weeks after Trump ordered troops out of parts of Syria after Turkey threatened to invade northern areas. The withdrawal left American’s Kurdish allies in the lurch, sparking outrage in the military and Congress who said the U.S. was betraying a partner that was instrumental in crushing ISIS.

“We are not abandoning the Kurds,” Esper insisted, even as Trump’s allies in Congress said the president was doing exactly that.

Edelman, the former Bush Pentagon official, said he’s worried about how the department can stop the loss of trust.

"We didn't take anything over and establish puppet regimes in Europe after World War II," he said. "The sense that the United States has acted more often than not in a disinterested way by creating some semblance of world order has given us enormous ability to do stuff around the world. Trump is undermining that."

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