WASHINGTON — Senate Armed Services Committee Chair John McCain, a key congressional gatekeeper for Pentagon nominees, said he does not want the Trump administration to nominate any more executives from the top five defense firms to run the Pentagon.

In a hallway interview with reporters Tuesday, McCain signaled Defense Department nominees who had worked for the five biggest defense contractors would have problems getting approval from his committee. 

The statement amounts to a major setback for the administration as it lags on filling jobs across the federal government. 

"I said I did not want people from the top five corporations," said McCain, R-Ariz.  "We’ve had a couple, and that’s okay, but I don’t want [more of] them."

Notable industry figures up for DoD jobs include Patrick Shanahan, a Boeing executive tapped to be deputy defense secretary; Ellen Lord, the recent CEO of Textron Systems, for undersecretary for acquisition, technology and logistics; and David Ehrhart for U.S. Air Force general counsel.

It’s widely expected, but not yet announced, that John Rood, Lockheed’s head of international sales, will be nominated for undersecretary of defense for policy. The job is seen as the No. 3 civilian spot in the Pentagon.

Lockheed, Boeing, Raytheon, General Dynamics and Northrop Grumman are the top five largest defense contractors in the U.S.

McCain first raised concerns that the Trump team is leaning too much on industry at Shanahan’s June 21 confirmation hearing. The surprisingly contentious affair included McCain saying defense executives serving in the Pentagon is "not what our Founding Fathers had in mind."

"The answers that you gave to the questions, whether intentionally or unintentionally, were almost condescending, and I’m not overjoyed that you came from one of the five corporations that receive 90 percent of the taxpayers’ dollars. I have to have confidence that the fox is not going to be put back into the henhouse," McCain told Shanahan.

McCain has since said he wants nominees who are "totally objective, well known and well regarded" and voiced concerns the committee’s reform focus might be thwarted otherwise.

The top Democrat on the SASC, Sen. Jack Reed, said there is "real concern about the concentration of these people." He stopped short of saying it might derail nominees, calling it "a factor to be considered."

"If you’re drawing from one sector alone, you get this group-think possibility, which could be dangerous," said Reed, D-R.I. "I believe these people will scrupulously follow the ethics rules, but it's hard after working for a major corporation for 30 years to separate the appearance — when you’re making a decision — that you’re being influenced by your prior employment."

Told of McCain’s concerns, No. 2 Democrat in the Senate, Richard Durbin of Illinois, was inclined to agree.

"This administration has turned a blind eye to the whole question of conflicts of interest from start to finish, and it’s no surprise that at the Department of Defense, we’re running into the same thing," Durbin said.

But several other members of the SASC said nominees must be considered individually, including Sen. Mike Rounds, R-S.D., who suggested Shanahan may only need to recuse himself from Boeing decisions for a time to avoid conflicts.

"You want to have expertise in these areas, and you’re not going to find that expertise without somebody having worked in the industry," Rounds said. "That is a part of what we look at, but I didn’t think it would be disqualifying."

As nominee to be the U.S. Air Force’s top lawyer, Ehrhart is said to face particular scrutiny. As a retired one-star general, Ehrhart most recently served as lead attorney for Lockheed Martin on the F-35 program, a frequent target for McCain’s ire. Ehrhart previously served as the chief counsel of global sustainment at Lockheed.

Two sources highlighted Erhhart as the most egregious case of reach-out to industry, and both anticipated a tough nomination process.

Lord, meanwhile, seems confident in her nomination being a success. She resigned from her spot as Textron Systems CEO days after the June 27 nomination announcement and is currently serving in an "advisory capacity working for the president and CEO of Textron, Scott Donnelly, until her confirmation," said company spokeswoman Ashlyn Brodeur.

Since the SASC voted to approve Shanahan, he is poised for a full Senate confirmation vote to be the No. 2 civilian in the Pentagon.

McCain's comments came a day after the White House used its daily press conference to accuse Senate Democrats of obstructing its nominees and agenda.

Senate Minority Leader Chuck Schumer, D-N.Y., said in a floor speech Tuesday that if Majority Leader Mitch McConnell, R-Ky., brought three pending DoD nominees to the floor vote, "they will be approved."

Schumer did not name the nominees, and there are four awaiting a floor vote: Shanahan; principal deputy undersecretary of defense nominee Elaine McCusker; director of cost assessment and program evaluation nominee Robert Daigle, and assistant defense secretary nominee Robert Hood.