MIAMI — Just a few weeks ago, it seemed a formality that Patrick Shanahan, the former Boeing executive who currently serves as acting secretary of defense, would be the official nominee for President Donald Trump’s second Pentagon chief.

But on Wednesday, Sen. Jim Inhofe, the Oklahoma Republican who chairs the Senate Armed Services Committee, threw cold water on the idea that Shanahan is practically guaranteed the job.

“If he hasn’t done it until now — I’m not casting any accusations or even expressing how I personally feel — but if the president hasn’t done it by now, then apparently he’s not going to,” Inhofe told Bloomberg News when asked if he thought Trump would nominate Shanahan.

That comment comes as Shanahan has been increasingly vocal about his belief that he is the right man for the job. He told Defense One on Tuesday that he wants the job, and on Wednesday he told reporters traveling with him that he has positives to offer the department.

“I show up every day, put my shoulder to the wheel because I believe in what we’re doing,” he said while en route to Miami. “I want to make a contribution to national defense. And I believe I can deliver on the National Defense Strategy.”

Part of the reason Shanahan was seen as a likely successor to Jim Mattis was because Trump has expressed personal affinity for the former executive. But assuming Trump — whose White House has been characterized by officials rapidly falling in and out of favor — hasn’t soured on Shanahan, what could be the hold up?

A March 22 Politico story points to the ongoing Inspector General investigation into Shanahan as a major factor that’s putting his nomination on hold. The IG investigation was launched after the government watchdog CREW — or Citizens for Responsibility and Ethics in Washington — questioned whether Shanahan, who worked at Boeing for 30 years, breached his ethics arrangement in favor of his former employer.

Shanahan may be the most prominent figure within the administration whose ties to industry require recusals, but hardly the only one.

In addition to Shanahan, those requiring ethics agreements include Under Secretary of Defense for Policy John Rood (Lockheed Martin); Under Secretary of Defense for Acquisition and Sustainment Ellen Lord (Textron Systems); Under Secretary of Defense for Research and Engineering Mike Griffin (Schafer Corporation); Chief information Officer Dana Deasy (JPMorgan Chase); Secretary of the Army Mark Esper (Raytheon); Under Secretary of the Army Ryan McCarthy (Lockheed Martin); and others all require some form of recusal from companies dealing with the Defense Department.

But none of those individuals have come under investigation, nor, with the exception of Esper, are any of them considered potential defense secretary candidates.

Speaking Wednesday, Shanahan expressed confidence the IG report would find no wrongdoing, saying: “I welcome it. It’s not an issue to me.”

“I appreciate the IG addressing these accusations,” he added. “What I would say is, look, I have over 30 years of experience doing large-scale engineering and manufacturing. I’ve brought that experience, management expertise to the Department of Defense. What I would tell people is I’m not at all biased towards Boeing. I’m biased toward performance for the Department of Defense, I’m biased toward performance for the taxpayer and most importantly I’m biased towards performance for the war fighter.”

He then seemed to point directly at one of the prime accusations in the CREW complaint — that he referred to the F-35 Joint Strike Fighter as “f---ed up” — saying the jet’s manufacturer, Lockheed Martin, “doesn’t know how to run a program.”

“I would also add: I know substandard industry performance. And I am an equal opportunity critic of substandard-performing programs. And I will always criticize substandard performance,” Shanahan said. “My history has always been to call things the way I see it because at the end of the day, that’s what our war fighters deserve and that’s why I joined the Department of Defense.”