President Trump on Wednesday announced his intent to nominate Christopher Miller, a senior Pentagon official in charge of Special Operations and combating terrorism, to head the National Counterterrorism Center — the agency set up after 9/11 to safeguard the nation from attack.

Miller, formerly the top counterterrorism official at the National Security Council, is seen as an experienced hand and career professional who can lead the agency at a time when its mission and effectiveness are under review.

But the move is also being seen with trepidation by some insiders who wonder if it is part of a Trump administration effort to purge the intelligence community of career professionals. The acting NCTC director, Russell Travers, a respected career intelligence officer with decades of experience, has held the line against cuts at his agency. And though he has long been expecting to retire, he did not learn of Trump’s intention to nominate Miller until Wednesday morning, according to a person familiar with the matter.

At the National Security Council, Miller, an Army Special Forces veteran with more than 30 years of government service, focused on pressuring the Islamic State, hostage recovery and hunting down the remnants of al-Qaeda’s leadership. On his watch, the Trump administration killed Islamic State leader Abu Bakr al-Baghdadi and a key lieutenant.

Miller also shepherded completion of the White House counterterrorism strategy in 2018 that expanded the scope of threats facing the United States to include Iran, Hezbollah and domestic terrorism. He moved to the Pentagon in December.

“I’m encouraged that the administration is turning to a career national security professional for this job as opposed to picking a career politician or some known ideologue,” said Nicholas Rasmussen, who led the NCTC from 2014 to 2017.

“What’s important is whether Chris Miller or any nominee can do what needs to be done most — which is to preserve the integrity and independence of the NCTC as an intelligence organization,” he said.

The counterterrorism agency has been helmed by Travers, who stepped into the position last August when then-Director Joseph Maguire was tapped by Trump to serve as acting director of national intelligence. Maguire was pushed out by Trump last month amid a controversy over a briefing given by an Office of the Director of National Intelligence (ODNI) official on Russian threats to the 2020 election. The president named a loyalist, U.S. Ambassador to Germany Richard Grenell, to serve as acting DNI until a permanent director is confirmed.

The ODNI is weighing cuts in funding and staff for the NCTC, which was set up in 2004 to ensure that information from any source about potential terrorist attacks against the United States was available to analysts. But as the Islamic State’s caliphate has been wiped out and al-Qaeda has diminished as a threat, policymakers are weighing whether to downsize the agency amid a shift to other priorities such as China, Iran and Russia.

The NCTC, which is the largest component within the ODNI, is not an operational entity. Rather, its roughly 1,000 personnel integrate analysis and collection from the government’s counterterrorism enterprise. They also operate a master database, from which the country’s terrorism watch list is drawn.

A review of the NCTC began in the summer of 2018 as part of a broader “transformation initiative” launched by then-DNI Daniel Coats. The goal was to gain efficiencies without cutting capabilities. As the largest of the four centers under the ODNI, the counterterrorism organization was a natural place to look.

“But it’s also a reality that NCTC has a line mission function that is unlike most of what the rest of ODNI does,” said a former intelligence official, who spoke on the condition of anonymity to be candid. That function incorporates authorities and abilities from various agencies across the intelligence community that no one spy agency possesses, the former official said.

At the same time, there is pressure to cut, and as a second former intelligence official put it, “The knives are out for NCTC in a pretty major way.”

Christopher Costa, a former special assistant to the president for counterterrorism who hired Miller onto the National Security Council, has known him since the 1990s, when they were both in Special Operations. He hired Miller as his eventual successor. “I wanted somebody who could lead that White House team, and Miller was the right guy at the right time,” Costa said. “I can’t think of anybody better suited to lead NCTC.”

Miller became senior director in the spring of 2018, eventually taking on the title of special assistant in the spring of 2019. Javed Ali, who preceded Miller as senior director and who is a former senior NCTC official, said Miller understands both policy and operations. “So now he’s bringing all of that experience — in operations, in Defense Department policy as a civilian and in NSC policy — to NCTC,” Ali said.

One of the main questions is how much latitude he would have to shape changes that are recommended, Ali said. “Hopefully he will have a fair amount of autonomy instead of being directed to implement a preexisting mandate.”