Biden transition: Why US spy world is feeling uneasy right now
A series of sackings and appointments - with rumours of more to come - has created a sense of deep uncertainty around the US intelligence and national security community.
While some outside that world have raised fears that this is part of an attempt by the president to hold on to power, many on the inside see it more as driven by a desire for personal revenge and the latest stage of a conflict that has done much to define Donald Trump's presidency.
But there remain fears that the uncertainty of a divisive transition could hold real dangers.
The sacking of a raft of top civilian leaders at the Pentagon, including the secretary of defence, was, many believe, just the start.
In some cases, this could relate to a president wanting to pursue specific policy goals during his final days and removing those who have opposed them, such as getting troops out of Afghanistan. But in many ways this also looks to some observers to be the result of pent-up anger and the final act in a long battle.
America's national security community has been in the firing line for President Trump, accusing it of being a "deep state" of conspiring against him.
He viewed the intelligence community assessment that Russia interfered in the 2016 election in support of his candidacy, as a threat to the legitimacy of his victory and went on the offensive almost immediately. And he has never stopped.
In recent months, he has been pushing hard to declassify information which he thinks will support his case that the assessment was wrong. The White House has installed political allies as director of national intelligence who have supported that drive but they have still met with resistance.
CIA Director Gina Haspel has been talked of as currently in the firing line. She has walked a fine line since being appointed. Critics say she has been too close to the White House, citing among other things her appearance and applause for the president at his State of the Union speech.
But her supporters say she has played a careful game in trying to stay sufficiently on the right side of the president to protect the agency from being politicised, fearing that if she was fired, then a more partisan figure would be chosen to replace her. And her apparent unwillingness to declassify some aspects of the intelligence surrounding Russian interference in the 2016 election recently has drawn fire from the president's supporters.
An even more controversial sacking would be that of Chris Wray, director of the FBI.
President Trump is believed to be angry at the failure of federal law enforcement to investigate Joe Biden's son Hunter Biden over his foreign business connections and wanted some kind of replay of 2016 when then-FBI Director James Comey's public pronouncements surrounding Hillary Clinton's emails caused her damage in the closing stretch of the campaign.
While CIA directors are often, but not always, replaced by a new president, FBI directors are appointed for a 10-year term.
The highly-regarded head of the Cybersecurity and Infrastructure Security Agency (Cisa), Chris Krebs, has also been rumoured to be in trouble because a website run by Cisa called rumour control made clear that claims of vote rigging and fraud, including those pushed by the president and his supporters, were false.
There have also been concerns at appointments as well as departures.
Political operatives have been given senior posts at the Pentagon and one, Michael Ellis, made general counsel to the National Security Agency (NSA), reportedly against the wishes of its head, General Paul Nakasone.
That gave rise to concern that the Trump team may be trying to "burrow" individuals into the national security system where they can continue to play a role after 20 January, when Joe Biden is inaugurated as president. Another option is that it is simply a desire to reward loyalists and allow them to "pad their resumes" with the expectation they will soon be gone and carry out more controversial policies in the meantime.
While a new president may be able to replace many of these individuals and pick his own team, there are still concerns about the implications.
The refusal to acknowledge Joe Biden's win means the former vice-president is not yet receiving, as is customary, the presidential daily brief of intelligence about the threats the US is facing. The longer that goes on, the more the danger will be that it could have real-world consequences as a new national security team may be faced with issues that they will not have been prepared for.
There is also a risk other countries could also seek to take advantage of this period of uncertainty, for instance Iran, which may want to retaliate for the killing of General Qasem Soleimani by the US in January.
Difficult transitions can have real consequences for national security.
The commission into the 11 September attacks found that the short handover from President Bill Clinton to President George W Bush, because of the disputed 2000 election, may have contributed to the failure to stop the devastating attacks on New York and Washington by making it harder to get a new team in place and up to speed in time.