WASHINGTON — Jim Mattis could be headed to Capitol Hill soon to talk about his concerns with President Donald Trump’s defense strategy.

In an interview on ABC’s “This Week” on Sunday, House Armed Services Committee Chairman Adam Smith, D-Wash., said he would like to have the former defense secretary testify before his panel on national security concerns. Mattis was forced out of his military leadership role on Jan. 1.

“His views on what we should be doing around the world would be invaluable for members of our committee,” Smith said. “So we'd love to get his perspective on a wide variety of issues.”

The new committee chairman said he would not interrogate Mattis on “what did the president say about this, what did he do about that.” But he said the former Marine Corps general “is one of the most knowledgeable, capable experts we have on defense policy and foreign policy,” making him a potentially valuable resource for the committee.

Whether Mattis will be a willing witness on Capitol Hill remains to be seen.

On Dec. 20, Mattis announced plans to step away from Trump’s administration so that the president could find “a secretary of defense whose views are better aligned with yours.”

In his resignation letter, Matts wrote that he believes America “must be resolute and unambiguous in our approach to those countries whose strategic interests are increasingly in tension with ours.” That includes “treating allies with respect” and doing “everything possible to advance an international order that is most conducive to our security, prosperity and values.”

He also specifically mentioned both the Defeat-ISIS coalition of 74 nations and NATO as “proof” alliances that have benefited America. His resignation came just days after news broke that Trump wanted to withdraw all U.S. forces from Syria, saying that Islamic State fighters in the region had been defeated.

Trump initially called Mattis’ departure a “retirement” but then forced the defense secretary out two months earlier than Mattis had planned, installing Deputy Defense Secretary Patrick Shanahan as the acting official in his place. Trump later publicly claimed he had fired Mattis and said his work in regards to Afghanistan strategy was “not too good.”

In a farewell letter to Defense Department employees, Mattis wrote that the military’s leadership “remains in the best possible hands” and encouraged all troops and civilians there to “keep faith in our country and hold fast, alongside our allies, aligned against our foes.”

He has not spoken publicly since then.

Smith said in the interview he believes Mattis did a good job navigating the difficulties of the Trump administration, and said his warnings on American attitude towards allies should raise concerns among policy leaders.

“Our allies matter enormously, and the president treats them like dirt,” he said. “He insults them regularly, does not consult them, makes radical decisions via Twitter and then changes his mind the next day.

“Look, the world is big and complicated. The U.S. is not able to do everything on our own. We need allies, we need people to support us.”