WASHINGTON ― Democrats say President Donald Trump’s move last week giving the Pentagon authority to set troop levels in Afghanistan flies in the face of a longstanding tradition of civilian control over the military.

“It’s not what the Constitution provides for,” said Brian Schatz (D-Hawaii). “We still need civilian oversight of the military. I trust [Defense Secretary James] Mattis, but even the secretaries I trust and respect need oversight, and that’s his job.” 

Trump’s move to step away from military decision-making mirrors his actions in April giving the military more control over war-making in Iraq and Syria. The Defense Department said the change would give commanders greater flexibility to deploy troops in the field as needed. But it also would insulate the president from criticism, particularly in Afghanistan, where America has been at war for 16 years and where it has spent trillions of dollars with no end in sight.

The U.S. is expected to add as many as 4,000 troops in Afghanistan, according to The Associated Press, despite Trump’s campaign rhetoric denouncing nation-building and foreign wars. The Trump administration has yet to release its long-promised military strategy for Afghanistan, drawing criticism it was plunging further into a conflict without a real plan.

“Troop strength is not an end. It’s a means to an end,” Sen. Tim Kaine (D-Va.) said Thursday on Capitol Hill. “We don’t know what the strategy is. They need to bring a strategy to us, and then we can have that conversation.” 

The degree to which presidents assert control over their military commanders has varied over the years. Former President Barack Obama, for example, was repeatedly accused of micromanaging the military as he sought to wind down the wars in Iraq and Afghanistan.

“It was micromanagement that drove me crazy,” former Defense Secretary Robert Gates said in 2014.

Trump, who has offered public adoration of generals, appears to be going in the opposite direction.

The change is being received well by Republican lawmakers.

“That’s not outsourcing,” said Sen. Richard Shelby (R-Ala.). “He’s the secretary of defense. The president of the U.S. should always listen to his commander, chief of staff of the armed forces and the secretary of defense. That’s what they’re all about.”

Sen. Steve Daines (R-Mont.) said he had confidence in Mattis.

“I’m the son of a Marine myself,” Daines said. “I think having a four-star Marine as the secretary of defense is exactly the right person at the right time.”

Sen. Bob Corker (R-Tenn.), however, expressed a more moderate tone. The Senate Foreign Relations Committee chairman said he had confidence in the military’s ability to set appropriate troop levels, but added, “We also need to be careful to maintain civilian control over that.”

Mattis, the man who is now in charge of setting troop levels in the Middle East, only recently left the military. The retired general, whose nicknames include “Mad Dog” and “Warrior Monk,” was replaced as head of U.S. Central Command in 2013 by the Obama administration for his aggressive posture toward Iran. His nomination required a special exemption from a statute that prohibited commissioned officers from serving as secretary of defense until seven years after active duty. Many Democrats joined Republicans in supporting that waiver.

The question of who allocates troop deployment is one of great significance. Military commanders, for example, have historically recommended deployment of larger numbers of troops abroad.

The issue was briefly discussed at a Senate Foreign Relations Committee hearing on Thursday, where lawmakers debated drafting a new Authorization for the Use of Military Force against the so-called Islamic State. Kathleen Hicks, the senior fellow in the International Security Program at the Center for Strategic and International Studies, testified that that both the Pentagon and the White House had responsibility for use of force.

Mattis “should be held responsible for decisions on use of force, and so should the president, obviously,” Hicks said in response to questioning by Sen. Robert Menendez (D-N.J.). “So there is a civilian that remains, but it’s just one.” 

Other ways for Congress to maintain oversight over the military, Hicks added, included passing a new authorization of force, strictly enforcing the War Powers Act, and the power of the purse.

Trump’s decision to delegate troop levels “makes all the more of a compelling case for an AUMF to be passed,” Menendez said in agreement.