WASHINGTON >> President Donald Trump’s decision to allow his Pentagon chief to set U.S. troop levels in Afghanistan won’t mean an immediate infusion of troops but should improve management of the war effort, Defense Secretary Jim Mattis said today. Still missing: an overall Trump strategy for America’s longest conflict.

“I will set the U.S. military commitment, consistent with the commander in chief’s strategic direction,” Mattis told a Senate panel, announcing a break with past White House control over troop numbers.

Mattis made the announcement a day after being verbally hammered by Sen. John McCain, the Senate Armed Services Committee’s Republican chairman, for the administration’s failure to present an overarching strategy for Afghanistan. McCain said the U.S. is “not winning” in Afghanistan. Mattis agreed.

Forced from power after U.S. troops invaded in October 2001, the Taliban have been resurgent, increasing their hold on numerous areas of the country and inflicting heavy losses of Afghan security forces.

The U.S. has about 8,400 troops in Afghanistan, a cap set by President Barack Obama’s White House, which closely controlled troop numbers in Afghanistan, Iraq and Syria in a manner similar to the way the Bush administration handled such matters. Trump’s decision to delegate that authority to Mattis reflects the president’s view that wars are better managed by the Pentagon; he previously provided Mattis leeway to determine how many U.S. troops are in Syria and Iraq.

“This ensures the department can facilitate our missions and nimbly align our commitment to the situation on the ground,” Mattis said, adding that the essential U.S. goals in Afghanistan remain unchanged: help Afghan combat forces gain the upper hand on the Taliban, and hunt and kill Islamic extremists affiliated with al-Qaida and the Islamic State.

Some, however, questioned the wisdom of the president delegating such authority to the Pentagon.

Christine Wormuth, the Pentagon’s top policy official from 2014 to 2016, expressed confidence in Mattis’ judgment and said she wouldn’t be bothered by an arrangement in which the president gave his defense secretary the authority to adjust troop levels within a broad range set by the White House.

“To just say to Jim Mattis, ‘Do whatever you think is best,’ and for Secretary Mattis to be able to add 30,000 troops, for example, without having to get the president to approve that, strikes me as unhealthy,” Wormuth said.

“It certainly could be interpreted as the president kind of distancing himself from these profound decisions and specifically from what we’re doing in Afghanistan,” she added. “I have long been bothered by the fact that the Afghanistan war has become the silent war. … I don’t think most Americans are even aware of it, and this (decision) is not going to help that.”

In his testimony, Mattis said U.S. troop levels won’t necessarily change immediately. While he is expected to add at least a few thousand troops soon, Mattis said he will act after further consultation with other government agencies and in line with Trump’s strategic direction and Secretary of State Rex Tillerson’s foreign policy. He said he expects allied nations to contribute additional support troops as well.

Trump has said very little about his intentions in Afghanistan. The administration has been reviewing its options, and Mattis outlined an unchanged mission to the Senate Appropriations defense subcommittee. U.S. forces are training, advising and assisting Afghan forces so that they can defend their own country and “terrorists can find no haven” there.

Later, Mattis said he could imagine the U.S. helping train Afghan security forces “years from now,” even after the country is stabilized.

Obama ended the U.S. combat role in Afghanistan in 2014. Throughout his tenure, Obama’s White House reviewed even small changes in U.S. troop levels in Afghanistan. Trump came into office saying he intended to give his generals more authority. In April, he allowed Mattis to set U.S. troop levels in Iraq and Syria, where Americans are supporting local forces fighting Islamic State militants.

As for strategy, Mattis said the administration’s war approach is being developed in a broader context that includes Afghanistan’s neighbors, Iran and Pakistan, as well as India. All have political stakes in the outcome and Mattis spoke about the State Department putting diplomatic and economic pressure on these countries.

Army Gen. John Nicholson, the top U.S. commander in Afghanistan, has told Congress he could use an infusion of U.S. and allied troops to bolster support for the Afghan army.

The Pentagon had considered a request for roughly 3,000 more troops, mainly for training and advising. That decision, however, stalled amid the administration’s Afghan review and a push for NATO to contribute more troops.