In August, 50 former senior national security and foreign policy officials who worked in administrations from Richard Nixon to George W. Bush signed a letter vehemently opposing a Donald Trump presidency. He would be, they said, “a dangerous president and would put at risk our country’s national security and well-being.”

On Thursday, less than two days after Trump beat Hillary Clinton in one of the ugliest and most contentious presidential campaigns in memory, an intelligence analyst will sit down with Trump and begin to share the nation’s most coveted secrets with the president-elect.

Several U.S. counterterrorism officials told VICE News there’s a sense of dread in the intelligence community about Trump’s victory, and disgust over his harsh criticisms of their assessments on Syria and Russia, particularly the finding that Russia is responsible for cyberattacks in the U.S.

Deeply troubling for the intelligence community is the possibility that Trump will indeed follow through with things he proposed while on the campaign trail, such as “bombing the shit out of ISIS” and perhaps putting boots on the ground in Syria. Policies like this, officials said, will undermine U.S. counterterrorism efforts around the world.

“We didn’t realize this was a real possibility,” one intelligence official told VICE News. Like others, the official requested anonymity in order to speak candidly about Trump. “There’s a whole slew of things we don’t have a firm sense of at this point.”

Trump will receive the presidential daily brief, or PDB, a classified summary containing closely guarded national security secrets about covert U.S. operations around the world. A designated CIA analyst gives the PDB to the president. White House press secretary Josh Earnest said President Obama ordered that the briefing documents he receives daily immediately be made available to Trump, Vice President–elect Mike Pence, and “designated members of [Trump’s] team,” who will soon receive security clearances.

“This is an important part in ensuring the kind of smooth transition that President Obama has prioritized,” Earnest told reporters.

In the days ahead, Trump will select his national security team and start to shape national security policy and objectives in what surely will be one of the most critical aspects of his presidency. U.S. intelligence officials will continue to bring him up to speed on various portfolios about intelligence and counterterrorism programs.

The direction of national security policy will depend on Trump’s cabinet choices. Don’t expect to see John Brennan running the CIA or James Clapper as director of National Intelligence. Instead, Trump will almost certainly select his own people for top intelligence and defense posts, and topping the list of candidates is retired Lt. Gen. Michael Flynn, who has been serving as Trump’s national security advisor. Flynn has a solid resume, having previously served as the director of the Defense Intelligence Agency and assistant director of National Intelligence.

But Flynn fell out of favor with the intelligence community — because of his staunch support for Trump. At the Republican National Convention, Flynn led the crowd in chants of “Lock her up!” And he has referred to Obama as a weak and spineless president.

What will happen on the policy front? Nothing in the short term. The intelligence community is made up of traditionally nonpartisan institutions, and most officers are career employees who will continue doing the same things they’ve been doing; the NSA will still collect signals intelligence, and the CIA will still conduct its counterterrorism mission and covert drone war around the world.

Though there’s some bad blood between Trump and Republican members of Congress because they did not line up in lock step behind Trump, he and Republicans are in sync over the future of the Guantanamo Bay detention facility.

It will remain open and may, for the first time in nearly a decade, start to be repopulated with terrorists captured on the battlefield. The Obama administration’s attempt to close Guantanamo and release cleared detainees has been a sore point for Republicans, who have complained for years that the U.S. doesn’t have a workable detention policy.

Now the U.S. may get one that hearkens back to the first term of George W. Bush.

What will be far more difficult for Trump to do is bring back waterboarding and other forms of torture, which he vowed to do on the campaign trail. Congress outlawed waterboarding and passed an amendment making the Army Field Manual the law of the land, which means the techniques in the manual have to be adhered to by the military and Intelligence Community.

Intel officials also worry that Trump will double down on neo-isolationist policies. He has indicated he wants to tear up the Iran nuclear deal — a deal that the intelligence community had a hand in crafting. He also wants to vastly expand the surveillance state, which was already expanded by Obama.

Secretary of Defense Ash Carter sent a transition memo out to Defense Department personnel Wednesday morning, reminding them that they must “stay focused on our duty to confront our current challenges and any that might arise during this [transition] period.”