It leaves the nation confronting complicated questions about the relationship between government and independent law enforcement, the nature of Trump's use of power and possibly even the integrity of the presidency itself.

Trump already had Washington on edge three months into his term. But his sudden strike against Comey was unconventional even by his own standards, and immediately and significantly exacerbated the discord that has raged since he took office. It may also have delivered another damaging blow to his own viability and the goodwill he needs to build a successful presidency.

As a shocked Washington digested the implications of Trump's political decapitation of Comey, accusations from Trump critics began to fly, and his defenders struggled to summon effective counterattacks.

But this was not just politics as usual. Something very significant had just occurred: The President fired an FBI chief overseeing a probe into claims his own campaign colluded with Russia to meddle in last year's election.

FBI directors always serve at the pleasure of the President. But it was those circumstances that left everyone breathless.

"I think it is profoundly troubling for our democracy," CNN's senior political analyst David Gergen said. "(Trump) may not mean to, but he is giving the impression that he thinks danger is getting too close."

Whatever that turns out to be true or not, Trump's move raised several possibilities, neither of which are likely to end well for him.

First, there is the question of whether Comey firing marks a deliberate attempt to disrupt the Russia investigation -- which would potentially amount to an abuse of power.

Alternatively, Comey's dismissal made quickly on Tuesday afternoon following a Justice Department recommendation, will appear to be an impulsive swipe made with little forethought and or insight into consequences that hint at gross political negligence.

JUST WATCHED Cooper to Conway: Your answer makes no sense Replay More Videos ... MUST WATCH Cooper to Conway: Your answer makes no sense 02:52

Historical precedent?

News of Trump's breathtaking decision broke just before 6 p.m. ET after a comparatively normal Tuesday in Washington, which was digging in for the GOP's long campaign to navigate an Obamacare repeal bill through the Senate.

Everyone was left groping for a historical precedent and had the same thought at once: Watergate.

Trump's dismissal of Comey brought to mind President Richard Nixon's order for Attorney General Eliot Richardson to sack special prosecutor Archibald Cox in 1973 -- a move that unleashed political forces that would eventually bring him down in disgrace. (Richardson and a deputy refused and resigned instead.)

"The only historical parallel is the Saturday Night Massacre," CNN Presidential historian Douglas Brinkley said.

JUST WATCHED Comey's firing compared to Nixon 'massacre' Replay More Videos ... MUST WATCH Comey's firing compared to Nixon 'massacre' 01:13

CNN legal analyst Jeffrey Toobin accused Trump of a "grotesque abuse of power."

Most immediately, the firing of Comey spurs questions about the future course of the investigation into Russia election interference.

After all, the President will now have to nominate a new director changed with overseeing the investigation into his own associates -- raising immediate questions over the new FBI boss' independence.

Those who see a nefarious hand in the firing will note that every investigation into the Russia issue -- in the FBI and in Congress, will now be overseen by a Trump appointee or a Republican.

And any new FBI chief nominated by Trump -- who vowed Wednesday to replace Comey with "someone who will do a far better job, bringing back the spirit and prestige of the FBI" -- is now guaranteed a rocky and acrimonious confirmation process.

The rationale for the firing of Comey is also set to come under intense security.

JUST WATCHED Fallon calling for special counsel at DOJ Replay More Videos ... MUST WATCH Fallon calling for special counsel at DOJ 01:25

The rationale

Newly confirmed Deputy Attorney General Rod Rosenstein laid out a charge sheet related to Comey's handling of the Hillary Clinton email investigation which many Democrats believe cost their candidate the presidency last year.

Yet Comey's actions -- including publicly upbraiding the former secretary of state for her stewardship of classified information even though she was not charged -- were raucously backed by Trump on the campaign trail.

And Trump's team has never shown anything but contempt for Clinton's complaints about the way the email saga derailed her campaign.

So the idea that the President was suddenly motivated by a desire to clean up that episode seems far fetched.

Even if he was, critics want to know why Comey was fired on Tuesday with new questions about Russia swirling around the White House and not as soon as Trump took office.

The fate of the FBI investigation itself must also now be in question.

Despite Democratic antipathy, Comey still boasted a reputation for integrity. Amid the congressional shenanigans over the Russia matter, Comey's was easily the most authoritative voice. When he announced during a Capitol Hill hearing two months ago that his agents were probing for any links between the Trump campaign and Russian intelligence operatives, it put a much more serious cast on the entire episode.

Now that voice is silent.

Brookings Institution scholars Benjamin Wittes and Susan Hennessey, who is also a CNN analyst, said Tuesday's events raised profound legal and ethical issues.

"There's also no question that removing the FBI director in the midst of a high-stakes investigation of Russian influence in the inner circle of the President's campaign and White House is a horrifying breach of every expectation we have of the relationship between the White House and federal law enforcement," they wrote on the Lawfare blog.

Comey's dismissal and the administration's motivation will inject a new and time consuming new element into congressional probes into the Russia affair.

Investigations in the House and Senate, struggling with a mountain of evidence and political infighting had already looked to stretch on for months. Now they seem all but inevitable to stretch into next year least before they find answers.

JUST WATCHED Toobin: Trump admin going to put a stooge in Replay More Videos ... MUST WATCH Toobin: Trump admin going to put a stooge in 01:26

Political implications

Then there are the political implications unleashed by Trump's move for the White House itself.

The Russia drama has hounded this administration even before its first days in office, over claims of Moscow's interference in the election, Trump's affinity for President Vladimir Putin and ties to Moscow of aides like sacked national security adviser Michael Flynn and former campaign foreign policy adviser Carter Page.

Now it seems unlikely that the suspicions and accusation will ever go away and seem certain to inflict new damage on Trump's already compromised approval ratings.

At early on the White House seemed unprepared for the firestorm that quickly came its way on Tuesday evening.

Administration officials fanned out to talk to reporters outside the presidential mansion and headed to cameras to go on cable networks.

On CNN, Trump's counselor Kellyanne Conway told Anderson Cooper "this has nothing to do with Russia."

"Somebody must be getting $50 every time (Russia) is said on TV ... (This) has everything to do with whether the current FBI director has the President's confidence and can faithfully execute his duties," she said.

On Wednesday, deputy press secretary Sarah Huckabee Sanders will face a test of fire at the podium in the White House briefing room. One question she will face is whether the administration is seeking to close down the Russia probes.

After all, Comey is not the first to be shown the door for at least appearing to pose a threat to the White House.

On Monday, former acting Attorney General Sally Yates testified to senators about how she was fired days after warning that Flynn could be compromised by Russia. The administration insists she was dismissed for refusing to implement Trump's travel ban on residents of seven Muslim nations.

Preet Bharara, US Attorney for the Southern District of New York, who had jurisdiction over the area of Trump Tower, was also fired by the President.

The White House meanwhile appears at the very least to have sought to sow distraction in the House intelligence committee investigation into Russian election meddling -- which ended with the chairman of the panel, GOP Rep. Devin Nunes, having to step down with his independence besmirched.

Trump, meanwhile, has repeatedly spoken and tweeted in a manner that suggests he is trying to discredit the investigations.

"The Russia-Trump collusion story is a total hoax, when will this taxpayer funded charade end?" Trump tweeted the day before firing Comey.

While none of these examples proves clear wrongdoing by the White House, together they add up to a pattern that is fuels suspicion among Trump critics.

JUST WATCHED Who is James Comey? Replay More Videos ... MUST WATCH Who is James Comey? 01:05

Major challenge

One major challenge for the White House now will be to solidify support among Republicans and head off Democratic claims that a special prosecutor or independent probe into the Russian evidence is now inevitable.

Some Republicans, like Sens. Susan Collins, Lindsey Graham and Marco Rubio, did initially take the administration's rationale for dismissing Comey at face value.

But others are wavering.

Sen. Richard Burr, who chairs the Senate intelligence committee probe into alleged Russian election meddling, expressed extreme concern over Tuesday's events.

"I am troubled by the timing and reasoning of Director Comey's termination. I have found Director Comey to be a public servant of the highest order, and his dismissal further confuses an already difficult investigation by the Committee," the North Carolina Republican said in a statement.

Other Republicans struggled to make sense of the White House's behavior.

"Regardless of how you think Director Comey handled the unprecedented complexities of the 2016 election cycle, the timing of this firing is very troubling," said GOP Sen. Ben Sasse of Nebraska.

Arizona Sen. Jeff Flake meanwhile tweeted: "I've spent the last several hours trying to find an acceptable rationale for the timing of Comey's firing. I just can't do it."