Hours later, his words appeared to gain new meaning.

Trump and his aides received less than an hour's notice Wednesday before the Justice Department announced it was bringing in Robert Mueller , an ex-FBI director, as a special counsel to take over the investigation into Russia's election meddling. It was the third straight day this week that brought deeply damaging news to an increasingly beleaguered commander-in-chief.

When he learned of the development, Trump himself was in the middle of interviewing candidates for the FBI director post, which is vacant because he fired the last person leading the Russia probe. A half-dozen advisers -- led by his White House counsel, who first informed him of the decision -- crowded into the Oval Office to plot a response.

It was a blindside that will substantially escalate the investigation into the Trump campaign's dealings with Russia. It's also another reminder to an increasingly besieged President of the limitations on his own power, even within the executive branch.

"As I have stated many times, a thorough investigation will confirm what we already know -- there was no collusion between my campaign and any foreign entity," Trump declared in a crisp, 57-word statement released 80 minutes after news emerged of the Justice Department's decision, which aides say he dictated from the Resolute Desk in the Oval Office.

"I look forward to this matter concluding quickly," said Trump, who continued his FBI interviews even as news of the special prosecutor became public. "In the meantime, I will never stop fighting for the people and the issues that matter most to the future of our country."

The White House Wednesday night was aiming for a measured response to Mueller's appointment and ended the night relatively pleased at the muted approach they believed the President put forward.

But that clearly dissipated by Thursday morning.

"With all of the illegal acts that took place in the Clinton campaign & Obama Administration, there was never a special (counsel) appointed!" the President complained on Twitter

He added , "This is the single greatest witch hunt of a politician in American history!"

JUST WATCHED Democrats and the 'I' word Replay More Videos ... MUST WATCH Democrats and the 'I' word 01:55

Containing the fallout

As the President was meeting with four finalists for the suddenly vacant FBI post Wednesday, some aides hoped a quick decision could help turn the corner on another week that had already become one of the toughest of his nascent presidency.

Those hopes were dashed by news of the special prosecutor, which was ordered by Deputy Attorney General Rod Rosenstein in a letter Wednesday.

As the President held brief conversations with the FBI contenders, word reached the White House counsel's office on the second floor of the West Wing that the order had been signed.

The President wasn't asked. He was told.

"It's still sinking in," one administration official said, describing an air of uncertainty in the West Wing. "We were told about it. Not asked about it."

The surprise announcement frustrated Trump, according to his aides, who have now spent the past three evenings seeking to contain the fallout from a series of rapid-pace headlines that further complicate the ties between the President and Russia.

Inside the West Wing, staffers again clambered for a response. Only two days ago, press secretary Sean Spicer insisted there was no use for a special counsel.

"There's, frankly, no need for a special prosecutor," he told reporters Monday.

The terse statement Wednesday was issued under the President's name, the only comment of the evening. Trump and his chief of staff Reince Priebus gathered staff to bolster the mood, according to one senior White House official.

"Let them do their thing and we will do ours," one official said in describing the message in the meeting. "We're all in this together."

But elsewhere, signs of fresh chaos were emerging.

Advisers planning Trump's first foreign trip, which begins Friday, canceled scheduled briefings on the matter to avoid having reporters milling about the West Wing. Vice President Mike Pence roared away in his motorcade.

Kellyanne Conway, Trump's senior counselor who had been scheduled for an appearance on Fox News, abruptly canceled.

"It does seem a little chaotic over there, I gotta be honest with you," said her would-be interviewer Tucker Carlson, a frank admission from a host who regularly defends the administration.

Into the night, the White House struggled to contain its frustration. Senior advisers told junior aides to focus on their work and compartmentalize the latest round of drama, which now the West Wing has even less control over.

The President and those around him saw again Wednesday night the limits of his own executive authority, a feeling presidents before him have bemoaned and he has witnessed multiple times in his four months in office.

One aide described the mood in two words: "Chaotically dark."

JUST WATCHED Trump: No politician has been treated worse Replay More Videos ... MUST WATCH Trump: No politician has been treated worse 00:48

'Enjoy your life'

As for the President, his foul mood has only persisted, even as he approaches the major endurance test of an eight-day foreign swing to five countries.

People close to Trump say he remains angry and frustrated with his staff. Rumors of a shakeup -- which have shadowed the White House since the day Trump took office -- only increased in volume as the barrage of bad news continued.

Trump continues to strain the patience and emotions of his underlings, who find themselves struggling to understand the impulsive and often self-damaging behavior of their boss.

The frustrations extend beyond the White House. One senior GOP source -- who has been in regular contact with Rosenstein, who helped execute the Comey firing, but Wednesday signed the order naming a special counsel -- said the deputy attorney general had become angry and exasperated with the Trump White House over their handling of the Comey matter.

Rosenstein, who was so upset after last week's proceedings that he was "talking about packing his bags," is throwing Trump "overboard" with this special counsel, the source suggested.

Meanwhile, at the White House, staffers say they're exhausted after a week of arrows.

"It's just been three days straight of these 5:45 pm announcements," one aide said.

Trump has sought to mask any strain during his increasingly rare public appearances.

He emerged from his White House residence with a smile early Wednesday, blissfully ignoring reporters who shouted questions at him as he made his way across a sun-drenched South Lawn toward the Marine One helicopter.

Flying to Connecticut to deliver his first commencement address to a US military academy -- a yearly tradition all presidents generally fulfill -- Trump was accompanied by a collection of aides he's openly considering firing.

His remarks, which wavered between doses of inspiration for the young graduates and angry screeds on his rivals, previewed a coming battle.

"You have to put your head down and fight, fight, fight," he declared, before ending his remarks with advice he likely wishes he could take himself.

"Enjoy your life," he said.