Washington (CNN) Paul Manafort's latest legal debacle deepened the core intrigue underlying special counsel Robert Mueller's probe : Why have so many of President Donald Trump's associates been caught lying about contacts with Russians?

In a significant new twist in the 2016 election saga, a judge ruled Wednesday that Trump's ex-campaign chairman "intentionally" lied to investigators, breaking a deal he had reached as a cooperating witness.

The lies, including about meetings with a suspected Russian intelligence asset, were about issues intimately linked to Mueller's wider inquiry, which includes a look into whether there were any links or coordination between the Trump campaign and the Russian election interference effort.

How Team Trump has changed its story in the Russia probe

Taken in isolation, the new Manafort bombshell would have rocked any presidency, given his senior role in the Trump campaign. But for a White House as cloaked in suspicion as this one, after two years of stunning revelations about Moscow's election interference , it is yet more bad news that will fuel a feverish atmosphere and further crank up pressure on Trump's inner circle.

Like many of the stunning reveals from Mueller, the latest Manafort drama also offered tantalizing glimpses into the special counsel's web of investigation but provided no resolution to the long-running Russia puzzle.

Mueller has yet to provide any proof of a conspiracy or cooperation between the Trump campaign and Russians, despite obtaining convictions and guilty pleas from a string of the President's former associates.

But Wednesday's developments will be seen in an even more foreboding light given the multiple lies, changes of story and obfuscations offered by other Trump confidants about contacts with Russian officials or private citizens.

These include former national security adviser Michael Flynn's calls with then-Russian Ambassador to the US Sergey Kislyak, Donald Trump Jr.'s shifting story about a meeting with Russians promising "dirt" on Hillary Clinton and the President's own misrepresentations about a proposed construction project in Moscow.

None of these activities are necessarily illegal, making it even more difficult to understand why there was an apparent need to cover them up.

"This is the million-dollar question in the entire investigation," Rep. Mike Rogers, a Michigan Republican who's a former chairman of the House Intelligence Committee, said on CNN's "Cuomo Prime Time." "You just have to start asking yourself, why did all of them lie about their connections to the Russians?"

Manafort is 'doomed'

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The judge's ruling represents a personal tragedy for Manafort, 69, once a high-flying uber lobbyist in an ostrich skin jacket who racked up millions in consulting fees and huge debts before joining Trump's team.

"It's doom for Paul Manafort," said CNN legal analyst Jeffrey Toobin, referring to the likelihood that the increasingly frail former political operative's existing jail term for tax and bank fraud will now likely be extended. The end result could mean he dies behind bars.

But the wider legal and political ramifications of the ruling are also staggering and are likely to revive speculation about the reckoning that may eventually await Trump from Mueller's final report.

According to Judge Amy Berman Jackson , Manafort lied to the FBI, the special counsel and the grand jury about his contacts with Konstantin Kilimnik, a political operative who is believed to have ties to Russian intelligence.

The ruling partly relates to a meeting between Manafort and Kilimnik at a Manhattan cigar bar on August 2, 2016. Thanks to a botched legal filing last month by Manafort's lawyers, it has emerged that Mueller believes Manafort shared polling data and spoke about Russia-Ukraine policy with Kilimnik.

In a sealed hearing last week, one Mueller prosecutor, Andrew Weissman, told Jackson that Manafort's meetings with Kilimnik go "very much to the heart of what the special counsel's office is investigating."

Jackson, in voiding Manafort's plea deal, ruled that he had also lied about $125,000 he had received for legal bills and about an unnamed separate Justice Department investigation. She decided that Mueller's team did not prove that Manafort had lied on two additional matters -- over contacts with White House officials or about Kilimnik's role in an attempt to influence witnesses.

Manafort's counsel argued that their client did not intentionally lie about anything.

Sinister aim?

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But it is Manafort's interactions will Kilimnik that will draw most questions in the days ahead, amid rising speculation that Mueller is approaching the end of his investigation.

For instance, was Manafort lying because he is simply, as has been proven through months of legal proceedings that ended with a conviction on bank and tax fraud charges, a congenital liar?

Or did he have a more sinister aim?

Was he trying to cover up wrongdoing that was material to the investigation into whether there was cooperation between the Trump campaign and the Russians? Could his obstruction therefore be part of an attempt to protect the President in the hope of attracting a pardon?

Or was he simply operating independently, seeking to curry favor with key Eastern European figures to mitigate his own plight and financial exposure, given his millions of dollars in debt owed to Oleg Deripaska, a Russia oligarch?

"There appear to be two reasons why he may do it -- one, that he thinks he can get a pardon," said John Dean, White House counsel to President Richard Nixon at the time of Watergate, on CNN's "Erin Burnett OutFront."

"The second reason he might be lying ... is fear for his life and his own family's well-being ... he has been playing with Russian heavyweights who do not like to have anybody go in and testify against them or reveal their secrets," Dean said.

Former Trump White House lawyer James Schultz, currently a CNN legal analyst, raised the question of whether Manafort was acting on official business or merely trying to ease his personal troubles in meeting Kilimnik.

"Did it have something to do with trying to help the campaign or was it that he was trying to repay a debt that he owed?" Schultz said, referring to Manafort's alleged handover of polling data.

"Was he acting in the scope of duties as campaign chairman or was he acting in the scope of trying to protect Paul Manafort?" Schultz asked on CNN's "Anderson Cooper 360."

In other words, was Manafort meeting with Kilimnik to rekindle his own once-lucrative business relationships in Ukraine, where he worked for pro-Russia politicians, or seeking to coordinate with Russia to influence the election?

The answer to that question could go a long way toward revealing whether the most alarmist interpretations of the unfathomable links between Trump associates and Russia are part of a wider plot or just a web of murky, personal ties.

Mueller could already know the answer.