The Paul Manafort saga — and with it, the Robert Mueller investigation — has taken a very strange turn.

And somebody is lying. Maybe more than one somebody.

The bottom line is that President Trump's former campaign chairman is no longer cooperating with the special counsel — and that's just part of this bizarre twist.

The second part involves whether Manafort was or wasn't having secret meetings with Julian Assange. If that's true — and there are lots of denials — it would open up a whole new avenue on the elusive question of collusion with Russia.

Manafort, the veteran lobbyist and GOP operative, was riding on top of the world when Trump tapped him in 2016 to run the campaign. He was ousted months later after a New York Times report on shady business dealings, and has been in a tailspin since his work in Ukraine and elsewhere came under Mueller's scrutiny.

Manafort was convicted in August of bank fraud and tax fraud for, among other things, lying to obtain millions in loans to support his lavish lifestyle (including the infamous $15,000 ostrich coat). The campaign was not implicated in any of this, which mostly predated Trump's candidacy. After insisting on his innocence, Manafort pleaded guilty in a second case, to avoid another trial, and agreed to cooperate with Mueller. That seemed to many in the media an ominous sign for the president.

But now Mueller's prosecutors say in a court filing that Manafort busted his plea deal through "crimes and lies," that he repeatedly misled investigators, and the agreement is off. This blows his chance for a lenient sentence — he's looking at 10 or more years behind bars — and means the special counsel can seek indictments for additional crimes.

Lawyers for Manafort say their client "believes he has provided truthful information."

The upshot is that Mueller's office can't possibly use Manafort as a witness now, having shredded his credibility and branded him a liar.

Why would Manafort engage in such a self-inflicted wound? Media speculation suggests that he's either more afraid of some of the foreign characters he dealt with than of prison, or that he's still angling for a presidential pardon. No one really knows, including me.

The president, not surprisingly, went off on the "Phony Witch Hunt," tweeting that the special counsel's team is treating people "horribly & viciously" and that "Mueller is a conflicted prosecutor gone rogue."

The second part of the saga is even stranger. The Guardian reports that Manafort once held secret talks with Julian Assange in 2013, 2015 and (according to a "well-placed source") the spring of 2016 — the last period being when he was involved in the Trump campaign.

Months later, WikiLeaks dumped the huge trove of Democratic emails that had been hacked by Russian operatives.

"It is unclear why Manafort wanted to see Assange and what was discussed," the Guardian allows. Its timeline also suggests they had a preexisting relationship. But it's hard to fathom that as high-profile a figure as Manafort would walk into the Ecuadorean embassy in London, where Assange has been holed up for years, as a Trump campaign official rather than using an intermediary.

As it happens, Manafort is calling the claim "totally false and deliberately libelous," saying he's never met Assange or anyone else from WikiLeaks. Rudy Giuliani, Trump's lawyer, said to NBC that the story is "unequivocally fake news I am told."

And there's this from the WikiLeaks founder, who not only denied such meetings but called one of the two reporters on the story a "serial fabricator":

"Remember this day when the Guardian permitted a serial fabricator to totally destroy the paper’s reputation." WikiLeaks says it is "willing to bet the Guardian a million dollars and its editor's head that Manafort never met Assange."

Okay, the part about the editor's head is creepy.

Yet the Guardian, which won a Pulitzer four years ago for its reporting on leaked NSA documents, is putting its reputation on the line.

So here's where we are: Paul Manafort said he was innocent. Robert Mueller had him twice indicted on criminal charges. Manafort admitted he was a crook in one case and Mueller agreed to a plea if the defendant would now tell the truth. Now Mueller says Manafort has since been lying and Manafort says that's not true. And the Guardian says Manafort met secretly with Julian Assange, but Manafort and Assange say that's a lie.

Hoping that clears things up.