Sen. Jeanne Shaheen (center) talks with Sen. Thom Tillis (right) on Capitol Hill in Washington, on Wednesday, Feb. 7, 2018. The two senators will co-chair a newly revived Senate observer mission to NATO. Also pictured is Sen. Joni Ernst (left). (Susan Walsh/AP)

Senators are resuscitating an observer mission to NATO that has been defunct for over a decade in the latest effort from Congress to affirm its commitment for the nearly 70-year-old alliance at a time when the president’s support for it is in question.

Sens. Jeanne Shaheen (D-N.H.) and Thom Tillis (R-N.C.) announced the reconfiguration of the Senate NATO Observer Group on Wednesday afternoon, stressing that Senate leaders, senior officials from the State and Defense departments, as well as U.S. Ambassador to NATO Kay Bailey Hutchison, were fully behind the effort.

But the senators said they had not yet secured the express buy-in of the White House and President Trump — whose own comments about traditional security alliances such as NATO have not always been in lockstep with those of his administration.

Discussions about reviving the observer group, which was first constituted in 1997 to help lawmakers stay engaged in plans to expand NATO into Eastern Europe but has not been in existence since 2007, began in earnest late last summer, just a few months after Trump’s first trip to Brussels, where he met with the leaders of NATO member states. While there, Trump scolded allies for not budgeting more toward their defense obligations to the alliance, and he held back making an unconditional endorsement of Article 5: that an attack on one NATO member would be treated as an attack on all.

Since then, the Senate has taken steps to demonstrate the United States’ commitment to NATO, such as adopting an amendment reaffirming support for Article 5 in a bill stepping up sanctions against Russia and Iran. But Shaheen said Wednesday that when in Munich in February to attend an international security conference, she heard fewer concerns from NATO allies about U.S. commitment to the organization.

“I didn’t hear from people on this trip that there were the same questions about where the United States was going to be with respect to NATO. . . . It was more of a discussion of how we’re going to go forward together,” she said.

“I think the fact that we had assistant secretary [A. Wess] Mitchell is an indication that the administration supports this effort,” Shaheen added, referring to the assistant secretary of state for European and Eurasian affairs, who came to Capitol Hill with Supreme Allied Commander of Europe Gen. Curtis Scaparotti to join Shaheen and Tillis on Wednesday to announce the new observer mission.

Tillis also noted that the high-ranking administration officials backing the effort show “that we clearly have the support of the administration and I think we’ll build on it.”

The observer mission is currently made up of 10 members of the Senate, but there are no limits on how big it can become. Present members include the chairmen and ranking members of the Senate Foreign Relations, Armed Services, Intelligence, and defense appropriations committees, as well as Shaheen and Tillis, who will co-chair. Other members will be selected by Senate Majority Leader Mitch McConnell (R-Ky.) and Senate Minority Leader Charles E. Schumer (D-N.Y.), and likely appointed in bipartisan pairs.

The group plans to make several trips to NATO allies “and make it very clear to them America’s commitment is strong,” Tillis said.

He and Shaheen added that the observer mission could play an important role in educating senators not on national security panels about the need to support NATO through increased appropriations and other legislative means — particularly in the face of terrorism, cyberthreats and Russian aggression.

“We’re building on what I think has been a remarkable year: increased participation, financial participation,” Tillis said, referencing how several NATO members had increased their defense contributions to the alliance. NATO members are expected to try to devote 2 percent of gross domestic product on defense by 2024.

“There’s a lot of positive momentum I think we can build on,” Tillis added, predicting that the administration would take steps “in the coming weeks” to step up sanctions against Russia.