Pat Shanahan, a former Boeing executive, risks being overpowered in internal debates by Trump aides such as national security adviser Bolton and Secretary of State Mike Pompeo, say former U.S. officials | Stephen Brashear/Getty Images US defense secretary faces Iran test Can Trump’s untested Pentagon chief handle the Iran hawks?

The Trump administration’s saber-rattling at Iran has skeptics of military action concerned about the inexperience of acting Defense Secretary Pat Shanahan — and whether he can stand up to longtime hawks like John Bolton.

Shanahan had held no government posts before joining the Pentagon nearly two years ago, and in his four months leading the Defense Department he has been less inclined than his predecessor, Jim Mattis, to resist President Donald Trump’s most dramatic impulses.

Now the former Boeing executive risks being overpowered in internal debates by Trump aides such as National Security Adviser Bolton and Secretary of State Mike Pompeo, say former U.S. officials who worry that the administration is on a path to war. Those fears were inflamed by a New York Times report Monday that said Shanahan had delivered Bolton a plan that could send as many as 120,000 troops to the Middle East if needed to respond to a provocation.

Mattis, who resigned in December after a dispute over Trump’s Syria strategy, repeatedly watered down or slow-walked Trump policies that military brass opposed or felt uncomfortable with, including on Iran and a 2018 missile strike on Syria. But Shanahan’s critics say he has far less leverage to do so — even if he was so inclined.

"Shanahan, in that group, is the weakest link,” said a recently departed senior Pentagon official, speaking anonymously to discuss sensitive internal deliberations. “Shanahan hasn’t been around these kinds of decisions and has zero policy experience and zero military experience. Mattis had experience and gravitas that Shanahan simply doesn’t have, and Bolton has years of experience in dealing with bureaucracy in this town, which gives him a huge advantage."

Ilan Goldenberg, a longtime foreign policy expert who served in both the Pentagon and the State Department in the Obama administration, agreed with that assessment.

“Shanahan is certainly outmatched by Bolton and Pompeo,” said Goldenberg, who is now at the Center for a New American Security. “He has neither the bureaucratic experience or political leverage to fight with them."

Bolton and Pompeo have trained rhetorical fire on Tehran in recent weeks: Bolton, an advocate of Iranian regime change who has served under four presidents, has threatened “unrelenting force” against any Iranian aggression. And Pompeo, during a stop in Europe this week, argued for a hard line in meetings with U.S. allies.

The latest developments in the White House's "maximum pressure" campaign against the Islamist regime and its proxies include tougher economic sanctions and dispatching additional bombers and warships to the region. Trump declined Tuesday to rule out military action, even while denying the Times' report that his administration had drawn up plans to send 120,000 troops.

"Now, would I do that? Absolutely," Trump told reporters. "But we have not planned for that."

He added: "If we did that, we would send a hell of a lot more troops than that."

The report of a new military option has set off fresh concerns about a possible march to war at a time when the Pentagon has an untested leader who may have far more difficulty than Mattis did in shaping Trump's decisions. Trump hasn’t yet nominated Shanahan to be permanent secretary, although the White House tweeted last week that he “intends to.”

Shanahan has led the Pentagon since January — the longest stretch ever for an acting defense secretary. Before that, the Senate confirmed him in 2017 as deputy secretary under Mattis.

A lack of more moderate voices in the administration's national security leadership was a major concern in both parties in the days after Mattis resigned over Trump's abrupt decision to pull American troops out of Syria.

“I want someone like Mattis who will tell the president the truth to his face,” Senator Tim Kaine (Democrat-Virginia), a hawkish member of the Senate armed services committee, told POLITICO at the time.

Republicans also expressed concern then that Mattis' resignation, following the departures of former National Security Adviser H.R. McMaster and White House chief of staff John Kelly, meant that Trump would be relying on a much narrower set of viewpoints.

During Mattis’ tenure as defense secretary, the White House was often frustrated with Pentagon resistance to more aggressive moves against Iran and its allies, according to a current defense official who was not authorized to speak publicly about internal debates.

The official pointed to the slow-rolling by Mattis, a retired general, and Joint Chiefs Chairman General Joe Dunford on military options against Iran's key ally Syria last year. In that instance, Mattis and Dunford pushed Trump toward the most limited item on his menu of proposed military options — a set of missile strikes against Syrian chemical weapons facilities — by painting it as more muscular than it really was.

Shanahan is now contending with the outsize personalities of Bolton and Pompeo. Bolton previously served as ambassador to the United Nations and undersecretary of state for arms control and international security affairs, while Pompeo, a former congressman and Army officer, was Trump's first CIA director.

Shanahan "likes to say that he earned a Ph.D. in world affairs as Secretary Mattis's deputy, and he draws on his 17 months of experience and tutelage as deputy secretary" in his new role, said Shanahan's spokesperson, Lieutenant Colonel Joe Buccino. And Shanahan has also recently won over former skeptics such as Senate armed services Chairman Jim Inhofe (Republican-Oklahoma), who promised Tuesday to hold his nomination hearing "as fast as possible."

Many in the Pentagon clearly think Shanahan is up to the task. While “he would not have been a good SecDef” two years ago, “he absolutely has the experience and knowledge to hold his own in interagency debates today,” said a second current defense official who was also not authorized to speak publicly.

Mattis trusted Shanahan to chair updates from commanders on the wars in Afghanistan, Iraq, and Syria during his time as deputy secretary, the official said, and Shanahan also received “more than 500 intelligence briefings” in that role.

But the Pentagon has already lost one Iran policy battle under Shanahan, during bureaucratic tussles over the decision to designate Iran’s Revolutionary Guards Corps as a terrorist organization. The White House and State Department supported the move, but the Pentagon opposed it on grounds it might lead Iran to retaliate against American troops and facilities in the region.

During that debate, Shanahan largely allowed his subordinates who were holdovers from Mattis’s team to “carry the water” on the Pentagon’s argument without challenging Bolton and Pompeo himself, POLITICO previously reported.

The recently departed senior Pentagon official said Shanahan’s slow, deliberate management style may also not be conducive to the fast decisions he could have to make during a military confrontation involving large numbers of troops.

“Shanahan has no experience with this — what kinds of things can happen as you mobilize and deploy forces, how escalation works, what it signals to foreign governments," said another former senior defense official who still advises Pentagon leaders. "He’s never done any of this, whereas Bolton and Pompeo have been at this a long time. How seriously are they going to take him?”

The first former senior defense official echoed those concerns, citing the battlefield options that Shanahan would have to help choose.

“There are very consequential decisions that will have to be made," the former official said. “Shanahan has a management style that’s well known in the building and avoiding and delaying decisions. That’s not what you need in the top seat in this situation.”

Moreover, Shanahan “will also have to sell any intervention to the Hill and make troops feel confident about his leadership," the former official added. "It’s not clear he can do either successfully."

On Tuesday, both the U.S. and Iran made notable efforts to lower the temperature, at least for now.

“We don’t seek a war, and they don’t either," Iran's supreme leader, Ayatollah Ali Khamenei, said on state television. "They know it’s not in their interests."

Pompeo, speaking in Moscow alongside Russian Foreign Minister Sergey Lavrov, said that "we fundamentally do not seek a war with Iran."

Also speaking out was John Abizaid, a retired general and Trump’s ambassador to Saudi Arabia. He urged caution in reacting to a spate of apparent drone attacks and other alleged sabotage that targeted Saudi oil tankers and facilities in recent days. While Iran immediately emerged as a suspected culprit, Abizaid called for letting investigators determine who was responsible.

“We need to do a thorough investigation to understand what happened, why it happened, and then come up with reasonable responses short of war,” Abizaid told reporters. “It’s not in [Iran’s] interest, it’s not in our interest, it’s not in Saudi Arabia’s interest to have a conflict.”

An official from an Arab country also told POLITICO that it appears that Trump himself is deeply uneasy about engaging Iran militarily.

As the tensions simmered Tuesday, however, whose judgment would prevail on Trump was prominent on the minds of many.

“We don't have a Secretary of Defense who's a decorated 4-star Marine Corps general with decades of military leadership experience, and we don't have a National Security Advisor with comparable, significant, national security leadership experience," Senator Chris Coons, a Democrat from Delaware and member of the foreign relations committee, said in a statement.

"The President did benefit from such a team in his first couple of years," he added, "and he did not launch any major new wars. I'm gravely concerned that we've got folks who are encouraging or tolerating his bumbling forward into a major deployment into the Middle East without a clear strategy.”