WASHINGTON – Secretary of Defense Jim Mattis will travel to NATO headquarters for the first time next week, a visit that will be closely monitored by allied nations concerned over President Trump's commitment to the trans-Atlantic strategic partnership.

Mattis will leave DC on Feb. 14 for Brussels, where he will attend his first NATO ministerial. He will also host a meeting of the defense ministers involved in the counter-ISIS coalition before traveling to the Munich Security Conference Feb. 17, the Pentagon announced Friday.

Pentagon spokesman Capt. Jeff Davis could not confirm if Mattis would have one-on-one meetings with all of the international counterparts, in part because the secretary's schedule was still in flux. But Mattis will undoubtedly prove a popular attraction for NATO countries seeking reassurance that the U.S. is not going to abandon them in the future.

The relationship between NATO and the new U.S. president has been tense ever since then-candidate Trump hinted in a July interview that his support for NATO nations would be conditional based on whether those countries had "fulfilled their obligations to us."

While Trump has since downplayed those comments, the allied nations remain nervous, especially in light of a detente between the Trump administration and Russia.

For his part, Mattis has repeatedly praised the alliance, both during his confirmation hearing in front of the Senate and in remarks since – part of a pattern of the the retired general playing good cop to Trump’s more bombastic foreign policy statements.

Since his nomination was first made official, members of Congress and defense experts have made no secret that they view Mattis as a check on Trump’s national security plan. Comments such as those of Senate Armed Services Committee ranking member Jack Reed, D-R.I., who cited Thomas Jefferson in saying Mattis would be the "saucer that cools the coffee," were scattered throughout Mattis’ congressional testimony – and Mattis himself did not push back against them.

But how much Mattis can do to push back against Trump, or even if it is his job to do so, is up for debate, said Mark Cancian, a defense expert with the Center for Strategic and International Studies who had worked with Mattis previously.

"It’s not the role of any Cabinet secretary to manage the president. The president is in charge, everyone else is expendable, except arguably the first lady. So ultimately, Trump will be making these decisions," Cancian said.

"On the other hand, Mattis has made it clear he’s willing to disagree with the president," Cancian added, citing Trump’s repeated comments that he believes torture is effective but would defer to Mattis on the issue. "And Trump seems to be comfortable with that. He has a Cabinet, many of whom have disagreed with his statements during their confirmation hearings, and Trump has said he’s good with that."

NATO has proven to be a test case of this strategy.

In his first statement after becoming secretary, Mattis emphasized that "recognizing that no nation is secure without friends, we will work with the State Department to strengthen our alliances."

That theme also sticks out in the public statements released by the Pentagon about Mattis’ first international calls. A series of readouts from his first week in office -- summary reports released by the Pentagon after major discussions between the secretary of defense and his international counterparts, in which the Pentagon puts forth the public spin it wants on discussions -- shows a clear trend in wording:

  • A Jan. 23 call with Canadian Minister of National Defense Harjit Sajjan, his first call to a foreign leader since taking office, during which "the two reiterated the depth and breadth of the relationship shared between the United States and Canada as NORAD partners, NATO allies, and North American neighbors."
  • A Jan. 23 call with UK State Secretary for Defense Michael Fallon, in which Mattis "emphasized the United States' unshakeable commitment to NATO and he thanked Secretary Fallon for his country's commitment of two percent of GDP to defense and contributions to international security."
  • A Jan. 23 call with NATO Secretary General Jens Stoltenberg, where Mattis emphasized his previous experience with NATO. "The secretary, who previously served as NATO's Supreme Allied Commander for Transformation, wanted to place the call on his first full day in office to reinforce the importance he places on the alliance. The two leaders discussed the importance of our shared values, and the secretary emphasized that when looking for allies to help defend these values, the United States always starts with Europe."
  • A Jan. 26 call with German Minister of Defense Ursula von der Leyen featured talk of "the importance of the alliance between the United States and Germany, both bilaterally and as members of NATO. The secretary assured the minister of the United States’ enduring commitment to the NATO alliance."
  • A Jan. 26 call with French Minister of Defense Jean-Yves Le Drian involved talk of "the importance of the NATO alliance and counter-ISIL operations, and thanked Minister Le Drian for his country’s continued commitment to both."

Cancian said those comments represent a conscious decision by Mattis to signal to partners and allies who might be nervous about Trump’s comments.

"I think Mattis is signaling that alliances are still important. He has a lot of experience as a warfighter and as a combatant commander, and understands the importance of having allies and intelligence, integrating that with combat operations," Cancian said. "On the other hand, that’s doesn’t mean the administration can’t push the allies to do more, to increase their share of the burden, and there are many ways they can do that. So the two don’t necessarily have to be incompatible."