The Senate Foreign Relations Committee this month will hear from Defense Secretary James Mattis James Norman MattisBiden courts veterans amid fallout from Trump military controversies Trump says he wanted to take out Syria's Assad but Mattis opposed it Gary Cohn: 'I haven't made up my mind' on vote for president in November MORE and Secretary of State Rex Tillerson Rex Wayne TillersonGary Cohn: 'I haven't made up my mind' on vote for president in November Kushner says 'Alice in Wonderland' describes Trump presidency: Woodward book Conspicuous by their absence from the Republican Convention MORE in a public hearing on authorizations for the use of military force — another sign of the growing momentum on Capitol Hill for updating the 16-year-old war authorization.

The committee announced Friday that Mattis and Tillerson will testify the evening of October 30.

Sen. Tim Kaine Timothy (Tim) Michael KaineNames to watch as Trump picks Ginsburg replacement on Supreme Court Barrett seen as a front-runner for Trump Supreme Court pick Biden promises Democratic senators help in battleground states MORE (D-Va.), a Foreign Relations Committee member who has long advocated for a new authorization for the use of military force (AUMF), applauded the announcement of the Mattis and Tillerson hearing.

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“The many questions surrounding the death of American servicemembers in Niger show the urgent need to have a public discussion about the current extent of our military operations around the world,” he said in a statement Friday. “For sixteen years, Congress has remained largely silent on this issue, allowing administrations to go to war anywhere, anytime.

“A new AUMF is not only legally necessary, it would also send an important message of resolve to the American public and our troops that we stand behind them in their mission.”

The pair has previously briefed the committee on the issue behind closed doors and has been asked questions about the issue in broader public hearings.

But the upcoming hearing is their first public one dedicated to the issue of war authorizations.

The Trump administration relies on the 2001 AUMF for legal authority in the war against the Islamic State in Iraq and Syria (ISIS), as did the Obama administration before it.

The AUMF authorized military actions against al Qaeda, the Taliban and other perpetrators of the Sept. 11, 2001, terrorist attacks. Proponents of using it against ISIS argue the terrorist group grew out of al Qaeda, while opponents highlight the two groups’ public falling out as well as the fact the ISIS did not exist when the authorization was issued.

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Trump administration officials have told Congress that it is not seeking a new AUMF, but that it would not oppose Congress passing one.

Mattis has said a new authorization would show the military that Congress, and by extension the American people, support their mission.

“As far as the AUMF goes, my point is that we need the unity of the American government, and with the Congress involved that brings the unity of the American people to this fight,” Mattis told the House Armed Services Committee earlier this month.

Several lawmakers have tried for years to pass a new AUMF, but effort after effort has stalled amid deep party divisions over issues such as how long the authorization should last and whether ground troops should be allowed.

This year, though, efforts have appeared to pick up momentum. A House panel surprisingly adopted an amendment to repeal the 2001 AUMF, though the provision was later stripped from the spending bill.

In September, the Senate voted against an amendment to repeal the 2001 AUMF, though the amendment had stronger support than expected.