WASHINGTON — The White House’s nominee to take over the Pentagon’s top policy job sparred with lawmakers over potential business conflicts with his last job, the latest episode in a series of fights over the President Donald Trump’s reliance on defense industry executives to fill senior military posts.

John Rood, in line to become the next under secretary of defense for policy, has previously served as acting undersecretary of state for arms control and deputy assistant secretary of defense for forces policy.

But his last job was as a senior vice president at Lockheed Martin International, where his responsibilities included “executing strategies to grow (the company’s) international business” and managing government relations activities overseas.

Senate Armed Services Committee member Elizabeth Warren, D-Mass., said she saw that as a problematic issue for his nomination.

“You were responsible for selling Lockheed’s products to other countries,” she said. “In you new role, you will be responsible for defense policy, including overseeing policy on foreign military sales to those same countries.”

Under department rules, Rood is already blocked from decisions directly related to Lockheed for two years, and required to divest himself from the company fully. But when asked if he would also recuse himself from policy discussions that may involve any foreign Lockheed sales, he demurred.

“Those issues that involve particular matters, something that involves the financial health of the company, I’m recused from,” he said. “If you’re describing a policy matter, such as how the United States should have a relationship with another country in an arms area, or cooperation between our air forces, I would be involved in that.”

The response drew criticism from Warren and a warning from committee Chairman John McCain, R-Ariz., that his unclear answers would cause “trouble” with his nomination.

“One of my major concerns has been the big five (defense industry companies) and the rotating back and forth between government and business,” he said. “This is a straightforward example of why we need straight answers.

“This isn’t something that should be difficult. You should not be making decisions that are related to your previous employment.”

McCain said he would request additional information from Rood before advancing his nomination. Several times in recent months, he has complained about the large number of Trump’s nominees coming from the defense industry, and had said Rood would be the last one he would support.

Whether he’ll withdraw that support now remains unclear.

Among major jobs filled from the defense industry are Patrick Shanahan, a Boeing vice president who is now deputy secretary of defense; Mark Esper, a Raytheon executive who is now Army secretary; Ellen Lord, a Textron executive who now heads the Office of the Under Secretary of Defense for Acquisition, Technology and Logistics; and Ryan McCarthy, the undersecretary of the Army who previously worked at Lockheed.

Rood’s nomination filled one of the last prominent vacancies at the Defense Department, bringing relief to some outside advocates who worry that the Pentagon is months behind on critical policy work without a permanent new leader there.

The post’s responsibilities include finalizing the new National Defense Strategy, under development since the spring. The document is designed to set Pentagon priorities for operations, readiness and spending.

Rood told committee members he would work to answer their concerns in the days to come. Lawmakers are scheduled to leave town later today for a week-long Thanksgiving break, before returning to Capitol Hill for four weeks of end-of-year wrap up work.