WASHINGTON >> Pushing back against explosive reports his own administration is conspiring against him, President Donald Trump lashed out against the anonymous senior official who wrote a New York Times opinion piece claiming to be part of a “resistance” working “from within” to thwart his most dangerous impulses.

Perhaps as striking as the essay was the recognition of the long list of administration officials who plausibly could have been its author. Many have privately shared some of the same concerns expressed about the president with colleagues, friends and reporters.

Washington was consumed by a wild guessing game as to the identity of the writer, and swift denials of involvement in the op-ed came today from top administration officials, including from Vice President Mike Pence’s office, Secretary of State Mike Pompeo and Dan Coats, director of national intelligence, and other Cabinet members.

Trump was furious, tweeting this morning that “The Deep State and the Left, and their vehicle, the Fake News Media, are going Crazy – & they don’t know what to do.”

On Wednesday night, Trump tweeted a demand that if “the GUTLESS anonymous person does indeed exist, the Times must, for National Security purposes, turn him/her over to government at once!” White House press secretary Sarah Huckabee Sanders called on the “coward” who wrote the piece to “do the right thing and resign.”

White House officials did not immediately respond to a request to elaborate on Trump’s call for the writer to be turned over to the government or the unsupported national security ground of his demand.

To some observers, the ultimatum appeared to play into the very concerns about the president’s impulses raised by the essay’s author. Trump has demanded that aides identify the leaker, according to two people familiar with the matter, though it was unclear how they might go about doing so. The two were not authorized to speak publicly and spoke on the condition of anonymity.

In a “House of Cards”-style plot twist in an already over-the-top administration, Trump allies and political insiders scrambled to unmask the writer. But the op-ed also brought to light questions that have been whispered in Washington for more than a year: Is Trump truly in charge? And could a divided executive branch pose a danger to the country?

Former CIA Director John Brennan, a fierce Trump critic, called the op-ed “active insubordination … born out of loyalty to the country.”

“This is not sustainable to have an executive branch where individuals are not following the orders of the chief executive,” Brennan told NBC’s “Today” show. “I do think things will get worse before they get better. I don’t know how Donald Trump is going to react to this. A wounded lion is a very dangerous animal, and I think Donald Trump is wounded.”

The anonymous author, claiming to be part of the “resistance” to Trump “working diligently from within” his administration, said, “Many Trump appointees have vowed to do what we can to preserve our democratic institutions while thwarting Mr. Trump’s more misguided impulses until he is out of office.”

“It may be cold comfort in this chaotic era, but Americans should know that there are adults in the room,” the author continued. “We fully recognize what is happening. And we are trying to do what’s right even when Donald Trump won’t.”

Trump raged about the piece in the White House, calling around to confidants to vent about the disloyalty of the author and fuming that the so-called Deep State within the federal government had conspired against him, according to a person familiar with the president’s views but not authorized to discuss them publicly.

First lady Melania Trump also weighed in, praising the free press as “important to our democracy” before attacking the writer, saying “you are not protecting this country, you are sabotaging it with your cowardly actions.”

The text of the op-ed was pulled apart for clues: The writer is identified as an “administration official”; does that mean a person who works outside the White House? The references to Russia and the late Sen. John McCain — do they suggest someone working in national security? Does the writing style sound like someone who worked at a think tank? In a tweet, the Times used the pronoun “he” to refer to the writer; does that rule out all women?

The newspaper later said the tweet referring to “he” had been “drafted by someone who is not aware of the author’s identity, including the gender, so the use of ‘he’ was an error.”

The Beltway guessing game seeped into the White House, as current and former staffers alike traded calls and texts trying to figure out who could have written the piece, some turning to reporters and asking them for clues. For many in Trump’s orbit, it was stunning to realize just how many people could have been the op-ed’s author. And some of the most senior members of the Trump administration were forced to deny they were the author of the attack on their boss.

Hotly debated on Twitter was the author’s use of the word “lodestar,” which pops up frequently in speeches by Pence. Could the anonymous figure be someone in Pence’s orbit? Others argued that the word “lodestar” could have been included to throw people off.

In a rare step, Pence’s communications director Jarrod Agen tweeted early today that “The Vice President puts his name on his Op-Eds. The @nytimes should be ashamed and so should the person who wrote the false, illogical, and gutless op-ed. Our office is above such amateur acts.”

Pompeo, who was in India, denied writing the anonymous opinion piece, saying, “It’s not mine.” He accused the media of trying to undermine the Trump administration and said he found that “incredibly disturbing.”

Coats later issued his own denial, followed by Defense Secretary James Mattis, Housing Secretary Ben Carson, Treasury Secretary Steve Mnuchin, budget director Mick Mulvaney and others; and with several prominent administration members delivering on-the-record denials, the focus could now fall on other senior aides to do the same, with questions raised about those who stay silent.

White House press secretary Sarah Huckabee Sanders tried to head off reporters’ inquiries of Trump officials, tweeting that the questions should be aimed at The New York Times, which she said was “complicit in this deceitful act.” Trump, appearing at an unrelated event Wednesday at the White House, lashed out at the Times for publishing the op-ed.

“They don’t like Donald Trump and I don’t like them,” he said of the newspaper. The op-ed pages of the newspaper are managed separately from its news department.

Down Pennsylvania Avenue, House Speaker Paul Ryan said he did not know of any role Congress would have to investigate the identity of the author, though Republican Rep. Mark Meadows of North Carolina, a Trump ally, said the legislative body could take part.

“Nothing in this town stays secret forever, and so ultimately I do think we will find out who is the author,” Meadows said.

The anonymous author wrote in the Times that where Trump has had successes, they have come “despite — not because of — the president’s leadership style, which is impetuous, adversarial, petty and ineffective.”

The assertions in the column were largely in line with complaints about Trump’s behavior that have repeatedly been raised by various administration officials, often speaking on the condition of anonymity. And they were published a day after the release of details from an explosive new book by longtime journalist Bob Woodward that laid bare concerns among the highest echelon of Trump aides about the president’s judgment.

The writer of the Times op-ed said Trump aides are aware of the president’s faults and “many of the senior officials in his own administration are working diligently from within to frustrate parts of his agenda and his worst inclinations. I would know. I am one of them.”

The writer also alleged “there were early whispers within the cabinet of invoking the 25th Amendment” because of the “instability” witnessed in the president.

The 25th Amendment allows the vice president to take over if the commander in chief is “unable to discharge the powers and duties of his office.” It requires that the vice president and a majority of the Cabinet back relieving the president.