President Donald Trump's decision to abruptly fire his defense secretary underscores the national security concerns posed by what is shaping up to be the most volatile and uncertain presidential transition in modern American history, former officials and experts say.
The firing of Mark Esper is raising fears that Trump will fire other key national security officials over the next 10 weeks and use his enormous power in the military and intelligence realm to act rashly before he leaves office.
Speculation is rampant inside and outside the government about whether Trump will also remove FBI Director Christopher Wray or CIA Director Gina Haspel, two experienced security hands who have displeased Trump by resisting some of his demands.
Even under the best of circumstances, a presidential transition "is a period when we aren't necessarily firing on all cylinders in terms of the people and processes that manage national security issues for the nation, which creates that sense of heightened vulnerability," Nick Rasmussen, a former head of the National Counterterrorism Center, told NBC News.
"This particular move today creates concern and uncertainty because there are already concerns about the president's decision-making style and what he might do in the remaining days of his presidency," he said.
The stability of U.S. national security institutions "is one of the mainstays of keeping America safe no matter what the threat, whether cyber, terrorism, or nation-states such as Russian, China or Iran," said Brian Katulis, a senior fellow at the Center for American Progress think tank. "When you make sudden shifts the way that he does in firing personnel at a time of transition it introduces even more uncertainty within the national security system."
Former CIA Director John Brennan bluntly articulated the worries of many current and former officials who spoke to NBC News.
"I think there is a lot that's going to happen over the next 75 days as Trump carries out vendettas, settles scores and tries to position himself for his next act," he said. "He is a totally unprincipled, unethical individual. I don't think anything is beyond him, and that's very scary to say."
Americans should be "apprehensive about what's going on," retired Gen. Barry McCafferty said on MSNBC. "We ought to be worried about this."
Sen. Mark Warner of Virginia, the ranking Democrat on the Senate Intelligence Committee, warned Trump in a statement not to fire anyone else.
“I’m deeply troubled by President Trump’s firing of Defense Secretary Mark Esper just 72 days before a new president will be inaugurated and during a growing global pandemic,” he said. “The transfer of power should be peaceful and fulsome in accordance with the principles that have animated our republic since its founding and the last thing that our country needs is additional upheaval in the institutions designed to protect our national security. President Trump must not invite further volatility by removing any Senate-confirmed intelligence or national security officials during his time left in office.”
Sen. Chris Murphy of Connecticut, a Democrat on the Foreign Relations Committee, spoke for many in his party when he said on Twitter, "Trump is creating a dangerously unstable national security environment during this transition period. Adversaries are watching."
Democratic Rep. Adam Smith of Washington, the chairman of the House Armed Services Committee, called the Esper firing a destabilizing move that will only embolden our adversaries and put our country at greater risk."
Even some Trump supporters expressed misgivings.
"Firing Esper is exactly the kind of chaos that cost Trump a second term," tweeted Marc Thiessen, a former speechwriter for George W. Bush who has called the Trump presidency "among the best of my lifetime."
"I have a grave sense of unease over the next 70 plus days," said Marc Polymeropoulos, a former senior CIA officer, told NBC News. "We face an enormity of overseas challenges, yet we have an angry, distracted and vindictive president who sees the intelligence community as his enemy, and thus will not be receptive to honest and direct intelligence briefings that provide the requisite warning function that keeps us safe. Does CIA Director Haspel even have any direct access to the president any longer? Must we count on the hopelessly politicized DNI Ratcliffe — a JV player on the national security scene if there ever was one — to be the only interface with the White House?"
Potential national security flashpoints, Polymeropoulos and other experts said, include rising violence in Afghanistan in the midst of peace negotiations and a debate over U.S. troops levels; continued Iranian support to Shia groups in Iraq that attack U.S. forces and diplomatic personnel; Chinese intimidation of Taiwan that could draw the U.S. into the conflict; and a rise of Islamist terrorist attacks in Europe.
Domestically, officials remain concerned about potential post-election violence, particularly among right-wing extremists who believe Trump's false claims that the election as stolen from him.
There are also worries about whether the Trump administration will spill state secrets. In the days since it became clear former Vice President Joe Biden had won the election, there have been calls among Trump supporters for John Ratcliffe, the director of national intelligence, to declassify more material related to the Russia investigation, despite qualms by some intelligence officials that doing so could compromise sources and methods.
"Will President Trump fire FBI Director Wray — and then selectively cherrypick and declassify top secret codeword intelligence that he believes muddies the water on the Russia investigation, putting sources and methods at grave risk?" Polymeropoulos asked.
The U.S. government badly wants to avoid a situation in which "our adversaries sense that vulnerability and weakness and have reason to question whether we can mount an effective response to whatever aggression or provocation they might throw our way," Rasmussen said.
"None of this guarantees that something terrible will happen over those 70-plus days," he added. "It just introduces a new wild card and a new source of unpredictability exactly at the time when we should be seeking to lean on sources of stability and predictability. And that's what gives me concern."