The Guardian is reporting that in March 2016, shortly before or around the time that he joined Donald Trump's campaign, Paul Manafort went to London to meet with Julian Assange and didn't sign in at the Ecuadorian embassy. First off, it's worth noting that embassies are almost entirely staffed by members of a country's intelligence community. So if you visit any embassy, that's who you're going to see. But let's set aside the colossal stupidity of this move and talk about the significance to the Mueller probe.
I know it's hard to keep track of the various different elements of the Mueller investigation, so let's quickly recap. Mueller indicted a bunch of Russians - most of whom will never see the inside of an American courtroom - for hacking the DNC servers and stealing emails. He also indicted a bunch of Russians at the Internet Research Agency for a coordinated attack on social media (mostly related to buying fake identities). So far we've got the actual hacking and we've got the social media disinformation campaigns. Mike Flynn and George Papadopolous (who is now in jail) both copped plea deals for lying to federal investigators about their contacts with various Russians. Paul Manafort was indicted, tried, and convicted, on a host of charges related to his work for Russian-adjacent oligarchs, although nothing that we've seen was specifically related to 2016 (more on that to follow). So the four buckets so far are: hacking the DNC (Russians), social media stuff (Russians), lying to federal investigators (Papadopolous, Flynn, and van der Zwaan), and, well, twenty years of rampant criminality (Manafort). It's worth noting here that the June 9, 2016 meeting that was attended by Manafort, Don Junior, and Jared Kushner, is a key focal point of the investigation even though no charges have been brought forth.
Now we move into the next phase of Mueller's investigation: the dissemination of the emails. We know that Roger Stone was DM-ing with the Russians posing as Guccifer 2.0. We also know he claimed to be in intimate contact with Julian Assange. We know that the Russians gave Wikileaks the emails they stole and that Wikileaks leaked them, timed to be as damaging as possible to the Clinton campaign. We don't know - but can suspect - whether Roger Stone knew specific details or if he and Jerome Corsi were just really good at guessing (that is, at present, Corsi's legal defense). Roger Stone and Paul Manafort worked together at a lobbying firm for years (nicknamed The Torturer's Lobby for their penchant for rehabilitating brutal dictators). Roger Stone was a close friend and confidante (to the extent he had either) of Donald Trump. It's been rumored that Stone suggested Manafort for the gig (more likely it was Rebekah Mercer). Anyway, they've met.
So let's put aside a whole big pile of the bullshit and focus on two things: Paul Manafort and Roger Stone. So far we know that Manafort (and Jared and Junior) met with the Russians who were offering a quid pro quo: Clinton emails in exchange for repealing Magnitsky Act sanctions. At the meeting - attended by 9 different high-level Russians and a...British music manager? - Manafort, Junior, and Jared claim that nothing happened. That nothing came of it. That 9 Russians flew halfway around the world for a big ole joke. And then - independently of this meeting - they hacked and released emails via Wikileaks that Roger Stone appeared to have intimate knowledge of and that were shared with Don Junior...for fun.
Let's take that on face value. So far we know about the quid pro quo offer in June 2016, and we know that close Trump associates were communicating with Wikileaks and the hackers, but we don't have a throughline connecting them.
Enter: today's news. If Manafort met with Assange, it could have been to shoot the shit or talk about their latest plans for Vladimir Putin and ruining Europe. It could have been any number of things. Coming, as it did, the month that Manafort got hired for free to manage Trump's campaign...the innocent explanations defy logic. We also know that the Russian hacking occurred in either March or April of 2016 (Manafort was announced on March 28 as the campaign manager). So we now have Manafort, who did most of his work for the previous ten years for Putin and his cutouts, meeting with Assange, another Putin cutout who would wind up disseminating the stolen emails, around the time that the emails were stolen in the first place, all of which occurred more or less concurrently with Manafort actively soliciting a job with no salary from Donald Trump. The two big silos - the hacking of the emails and the dissemination of them - are connected for the first time (seemingly) by this information. It now ties everything from March (the hacking and the hire of Manafort) to June (the meeting at Trump Tower) to August (Stone reaching out to Guccifer and Wikileaks) to October (the emails being dumped immediately after Trump's Access Hollywood tape was published) to November (the election) to December (Flynn calling Russia's spymaster-in-chief who - coincidentally - had a meeting attended by Trump in March 2016). Again, we don't know yet what exactly was discussed but it appears that the simplest answer is that the conspiracy is as big and as wide-ranging as most reasonable people suspected, and that Trump utilized a foreign power to commit myriad crimes to achieve the office of the Presidency. Following that, he appears to have engaged in a 2-year obstruction of justice process in order to shield himself and others from the negative consequences.
And if Mueller knows the meeting happened, imagine what else he knows.