In a city in which the Trump tempest whips up a daily torrent of news, it's like we're in the eye of the storm.

On this Thursday, that tempest has been stalled by a sensational announcement late on Wednesday that took even the President by surprise - his own Justice Department had decided the only way forward in the messy saga of his Russia connections was the rare appointment of a special counsel, effectively an independent investigation, with unimpeachable leadership.

Under an administration that leaks like a sieve, the considerable work that preceded the announcement by Deputy Attorney-General Rod Rosenstein was kept under tight wraps. There's been no indication yet that Rosenstein even consulted Jeff Sessions, his boss and Trump's attorney-general and confidant, who earlier in this crisis was obliged to recuse himself from the Russia fandango because of his own "truthiness" challenges.

But in selecting the near-sainted former FBI director Robert Mueller for the task, Rosenstein redeemed himself. Just a week earlier he was pilloried as the author of a document which, for a while, Americans were told was the justification for Trump's controversial decision to sack James Comey, the FBI director who had been in charge of the sprawling Russia investigation.

It's no surprise that Trump was stabbing at his Twitter keyboard over breakfast on Thursday. Without evidence, he bemoaned the failure to appoint a special counsel to investigate "all of the illegal acts that took place in the Clinton campaign & Obama Administration".

Trump cast himself as martyr. Suggesting he clearly appreciated the extent to which the political and legal threats to his four-month-old presidency had grown in menace, he added: "This is the single greatest witch hunt of a politician in American history!"

The President has good reason to worry - as do his staff, any of whom can expect orders to produce documents and/or to make themselves available for interrogation by Mueller's men.

Serial congressional inquiries will continue, but Mueller is the new pointy end of the spear. His appointment relieved Democratic fears that the GOP was using its numbers in the House and the Senate to sandbag the investigations.

The letter in which Rosenstein appointed his old colleague authorises Mueller to investigate links or coordination between Russia and Trump campaign officials, but also "any matters that arose or may arise directly from the investigation". And by invoking a Justice Department regulation that permits special counsels to investigate attempts to impede their inquiry, the letter is being read as an express instruction to get into Trump's sacking of Comey.

"Based upon the unique circumstances, the public interest requires me to place this investigation under the authority of a person who exercises a degree of independence from the normal chain of command," Rosenstein said in a statement.

Mueller is answerable to Rosenstein, but he is expected to have greater autonomy than other federal prosecutors. Sessions' recusal from the Russia investigations is also seen as a ring-lock fence that will protect Mueller from political interference as he leads an inquiry that has the power to lay criminal charges.

Rosenstein's artistry was in tapping Mueller. As FBI director, Mueller had been confirmed by a unanimous Senate vote and he had served both Republican and Democratic presidents - George W. Bush and Barack Obama. His reputation as one of the most credible law enforcement officials in the country ensured only warm welcomes on Capitol Hill.

Nebraska Republican Ben Sasse hailed Mueller's "record, character, and trustworthiness [which] have been lauded for decades by Republicans and Democrats alike".

Maryland Democrat Ben Cardin lauded Rosenstein's "important step toward restoring the credibility of the DOJ and FBI in this most serious matter".

Republicans might have argued that Mueller had too much baggage. He's very close to the sacked Comey and has a history of staring down presidents. In the wake of the 9/11 attacks on New York and Washington, he and Comey threatened to resign over George W. Bush's move to re-authorise the National Security Agency's warrantless wiretap program without changes.

Moving with such speed and deftness on Wednesday, Rosenstein lanced a boil that even some Republicans were beginning to acknowledge could not go untreated.

There has been a numbing element to endless shock-horror headlines since last year's revelation that Moscow had orchestrated the hacking of the Democratic Party's computers - an effort which the combined US intelligence agencies concluded was intended to help Trump defeat his rival, Democrat Hillary Clinton.

But in the last 10 days the story went into overdrive: Trump fired Comey; he lied about firing Comey; and he threatened the former FBI boss, implying publicly that he had recorded their conversations.

Meanwhile, as parsed by a DC wag, Trump was "blabbing secrets to [Russian Foreign Minister] Sergei Lavrov. Denying that secrets were blabbed. Then blabbing about blabbing to Lavrov."

The haste with which Trump dumped Comey and the reluctance with which he let national security adviser Michael Flynn go will exercise Mueller's mind - and so will all the interactions between the Trump campaign team and Russia.

We've heard about a few of them. But despite serial denials by the White House, Reuters reported this week that there were at least 18 previously undisclosed phone calls and emails between the Trump campaign and Russia in the last months of the 2016 campaign.

Conservative commentator Erick Erickson uses typical DC logic to conclude that Trump has nothing to worry about: "The odds are that the Department of Justice would not launch this sort of investigation if they did not already have an inkling of there being no real issues with the President. If they were really concerned about the President, they would keep this in-house, where they could exercise greater damage control."

Harvard law professor Laurence Tribe is punting on a more dramatic outcome: "It seems increasingly likely that the many parallel ways Trump, his family, and his White House team kiss up to Putin will ultimately be explained by the Russian trail of money and its laundering that is finally getting closer attention.

"But whether that's the tip of a grossly unconstitutional iceberg or just the strangest bunch of coincidences ever, we need to get to the bottom of the money pit through investigations beyond the reach of Trump's machinations."

Unlike Trump, Mueller sweats the details.

Thomas Pickard, who served as Mueller's deputy at the FBI, said that when it came to briefing his boss, Mueller would often reject summaries, asking instead to review the full notes taken by agents from their interviews.

"He's a real student - getting down into the details," Pickard said.

Mueller is the stuff of Justice Department legend. He was a senior prosecutor under the first president Bush, left to work in private practice and then returned - insisting that he go back to the bottom of the ladder, schlepping his books to court as a low-level prosecutor in Washington.

"He came in as a line assistant and he was legendary. He was the first guy there every single day," former colleague Preston Burton said. "All of a sudden he's doing street crime? Literal street crime. He's inexhaustible. He's the embodiment of integrity."

By contrast, the only consistent thing in Trump's pronouncements on the matters to be investigated has been his inconsistency.

First he said that Comey had been sacked because of his handling of the investigation of Clinton's email server; then it was because of "this Russian thing"; and on Thursday, he insisted that he had not been attempting to derail the Russia inquiry - "it had always been about the Clinton inquiry".

Similarly, as recently as early this week, the White House insisted there was "frankly no need" for a special investigator to examine the Russian meddling.

But in a statement on Wednesday evening, Trump said: "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. I look forward to this matter concluding quickly. In the meantime, I will never stop fighting for the people and the issues that matter most to the future of our country."

Trump is in more trouble than he's ever been, but he still retains his core support among Republican voters. This week, Gallup recorded it in the mid-80s, but slipping. Among all Americans, his support languishes at just 38 per cent.

His friend and self-described political dirty trickster Roger Stone is warning that Trump's cabinet colleagues are plotting a coup: "They're going to say that Donald Trump has Alzheimer's."

But there have been a few remarkable high-profile defections. The radio host Michael Savage has worried aloud that "the administration is in trouble".

And conservative firebrand and In Trump We Trust author Ann Coulter has been sighted on the road to Damascus - conceding in a recent interview that maybe "the Trump-haters were right", she said of the 45th presidency: "It has been such a disaster so far."

And even the editorial page of The Wall Street Journal is getting the wobbles, warning that his presidency was "sink[ing] before his eyes". It warns Trump: "Presidencies can withstand only so much turbulence before they come apart."

Alarmingly, there are reports of something akin to a ceasefire in some of the factional wars between aides at the White House. As it dawns on them that the administration may have squandered its credibility, all sides are venting anger at a single target - the President.

But Trump still has his defenders.

John Yoo, a deputy assistant attorney-general under George W. Bush, argues that comparisons with Watergate are misguided.

"Unlike in the Watergate case, there is no evidence that the President ordered witnesses to lie, destroyed evidence or tried to block FBI agents from doing their job. At least, no evidence yet."

But with Yoo's backward glance shifting from Nixon and Watergate to Reagan and the Iran-Contra scandal, it is difficult to envisage Trump acting as Yoo believes he must to save his presidency.

Urging Trump to emulate Reagan, Yoo writes: "He should fire his chief of staff, Reince Priebus, and his chief strategist, Stephen Bannon, and all the others who brought the chaos of the presidential campaign into the White House. He can replace them with more experienced government hands, much as he replaced Mr Flynn with H.R. McMaster. He can appoint an independent presidential commission to get to the bottom of the Russia affair, copying the Bush inquiry into Iraq's WMD program."

Pleading for Trump to allow Congress to deal with domestic policy and instead for the President to focus on national security and foreign affairs, Yoo warns: "The alternative is to spend his term in office floundering from one self-inflicted controversy to the next, exhausting himself amid a rising flood of investigations."

Despite reports that Trump is tossing around ideas for a staff makeover at the White House, it's difficult to see him making such wholesale changes because to do so would be to admit that he's in deep shtook.

A problem here is that Trump invariably figures he knows best. But a new SurveyUSA poll finds that a majority of Americans disagree.

Fifity-six per cent (including 1 in 4 Republicans) say Trump "sometimes loses touch with reality". Thirty-seven per cent say Trump "is unable to distinguish between what is true and what is made up".

As if to prove the poll correct, the Daily Beast reports that despite the litany of offences by his former national security adviser, the President still hopes to get Michael Flynn back on the administration payroll.

"Trump doesn't just hope that Flynn will beat the rap. Several sources close to Flynn and to the administration tell the Daily Beast that Trump has expressed his hopes that a resolution of the FBI's investigation in Flynn's favour might allow Flynn to rejoin the White House in some capacity - a scenario some of Trump's closest advisers in and outside the West Wing have assured him absolutely should not happen."

All this could happen only in Donald Trump's Washington.

And that noise you just heard, a bit like a gale-force wind? That was a sigh of relief from Trump as he readied to buckled himself in on Air Force One. He is due to leave early Friday, on his first overseas trip as President.