The tweet that could signal the end of President Donald Trump.

You’ve probably heard the words “Trump” and “impeachment” getting tossed around over the last couple of days. And something to do with a tweet and bloke named Flynn?

That’s because the Whitehouse is currently fighting off what is arguably the biggest threat to an administration since the Watergate scandal of the 1970s, after Donald Trump posted a tweet that some claim could lead to criminal charges and the downfall of his presidency.

Quick, get me up to speed. What’s the backstory?

OK, so… back in February – just 24 days into the Trump administration – a retired United States Army Lieutenant General named Michael Flynn was forced to step down from his role as the US National Security Advisor.

At the time, President Trump told media he’d requested Flynn’s resignation because he had given an incomplete account to then Vice President-elect Mike Pence of his conversations with Russian Ambassador Sergey Kislyak during presidential transition period a few months earlier. Essentially, Flynn had denied to Pence that (a) he’d discussed US sanctions against two Russian intelligence services and (b) that he’d asked Kislyak to delay the vote on a United Nations Security Council resolution that would be damaging to Israel.

LISTEN: Mia Freedman and Amelia break down the Flynn fallout, on our Trump podcast. (Post continues below.)

In a dramatic development on Friday, Flynn plead guilty to perjury after admitting he had also lied to the FBI about those conversations during the Bureau’s probe into the Trump campaign’s links with Russia back in December.

In response to the news, a tweet surfaced on President Trump’s account over the weekend that read, “I had to fire General Flynn because he lied to the Vice President and the FBI. He has plead guilty to those lies. It is a shame because his actions during the transition were lawful. There was nothing to hide!”

So, why is the tweet such a big deal?

The crucial bit here is that President Trump has mentioned that he knew Flynn lied to the FBI. He’s never said that before, and for good reason when you look at the sequence of events.

According to a statement previously given to a Senate Estimates Committee by sacked FBI Director James Comey, President Trump asked him to end the Russia/campaign investigation on February 14 – one day after the President had forced Flynn to step down.

In other words, the President has indicated that he knew Flynn had broken the law when he asked Comey to ditch the bureau’s probe into the matter (and then fire him three months later over his refused to do so).

Multiple legal experts and some Democratic lawmakers have said this could constitute an ‘obstruction of justice’; that essentially the President of the United States has unwittingly confessed to a felony in front of millions and millions of witnesses.

Realtalk, could Trump actually be impeached over this?

Well, President Trump’s lawyer, John Dowd, is now claiming he is behind the damning tweet. In an interview with Reuters that he had drafted the comment and said putting it together had been a “mistake.” “I’ll take responsibility,” Dowd said.

Still, potential fallout from the admission is bound to be making the Trump administration very, very nervous, because if obstruction of justice charges are laid and proved, it could spell the end of his presidency.

It’s difficult to pin down just what the chances of an impeachment may be – unless you’re a bookie: “Trading at a low of 1.7 or 4/6, which equates to a 59 per cent implied chance, punters are increasingly confident that this is one mess Trump will not be able to tweet his way out of,” a spokeswoman for Betfair told The Independent.

But let’s keep in mind, impeachment is a political process, not a legal one. As The Atlantic‘s Peter Beinart noted, passing an article of impeachment requires support of the majority of the House. “Were such a vote held today — even if every Democrat voted yes — it would still require 22 Republicans,” he wrote. “That kind of mass Republican defection has grown harder [to imagine] because the last six months have demonstrated that GOP voters will stick with Trump despite his lunacy, and punish those Republican politicians who do not.”

Could others be implicated in this mess?

The revelation that Flynn is now cooperating with authorities ought to make Trumps inner circle pretty nervous.

He’s the first member of the administration to have plead guilty to charges uncovered as part of special counsel Robert Mueller’s wide-ranging investigation into Russian attempts to influence the 2016 US election and potential involvement by President Trump’s officials. (Essentially, what Comey was looking into before his dismissal in May.)

Trump’s senior aides and several other campaign and transition officials – including his son-in-law, Jared Kushner – have denied having contact or knowledge of contact with with the Russians before the President took office in January. Trump himself has echoed that message, telling media over the weekend, “What has been shown is no collusion, no collusion. There’s been absolutely no collusion.”

But according to US media, court papers relating to Flynn’s guilty plea suggest that multiple senior staff were aware of his conversations to Russian officials in the weeks before the inauguration.

This could be big, folks. Huge. (Or should that be ‘yuge’?)