The initial exchange of e-mails arranging the 6/9/16 meeting was on 6/3/16. Trump’s tweet of 6/7/16 promised that he would give a major speech on 6/13/16 about newly hacked Clinton e-mails. The existence of the hack, and the possession of the hacked material by WikiLeaks, was announced on 6/12/16 by Assange, and on 6/14/16 by the WaPo. The fact that Trump announced something on 6/7, if only in a way that no one took literally before 6/12, was noted at the time, but not thought to mean that Trump was himself involved in the hack. That would have been way too conspiracy theory at that time, given our much more limited knowledge of Trump back in June of 2016. It was just assumed at that time that WaPo and perhaps other news outlets had at least preliminary word on the DNC hack, and that got out to Trump a week before WaPo, bolstered by Assange’s announcement two days before it ran the story, felt it had firm enough grounds to publish.
But now we know how Trump became aware of the coming publication of hacked DNC material. His son had, on 6/3/16, arranged a meeting to negotiate acquisition and/or exploitation of this material with Veselnitskaya and Akhmetshin. Then Trump’s tweet on the day of the meeting itself, written just after that meeting, makes two cryptic points, well, cryptic to those of us not in on his strategy at the time, but perfectly understandable now that we know about the 6/9/16 meeting in particular, and now that we have seen in general how the campaign unfolded. These two points involve two numbers.
The first number is 33,000. That, in ongoing alt-right mythology, is the number of e-mails deleted from her server by crooked Hillary to conceal God knows what criminal activity she conspired at while Secy of State. The Russians hadn’t hacked her server, that wasn't the material on offer at the 6/9/16 meeting. But, if you follow the axiomatic, foundational belief that those 33k e-mails must have been deleted because they contained evidence of Hillary crookedness, and then add the just-as-reasonable postulate that at least some of this criminal conspiracy would have been with folks at the DNC, then it follows that the mound of stuff hacked from the DNC, the stuff that Veselnitskaya was offering, must contain at least some of these 33k lost, incriminating, e-mails.
At this point in his campaign, everyone, even Trump himself it would seem, believed that he needed some sort of Hail Mary pass, some sort of big event or revelation, to win, because by all conventional calculations, he was going to lose. He was behind in the polls, nationally and in the battleground states, and he lacked the means that, conventionally, would allow him to recover. The size of Clinton's lead was never insurmountable -- if he had some means to make headway, to chip away at her lead. But that was his problem, he had none of the conventional tools to achieve that. It was way late in the game, and he had practically no staff, no campaign, a mere 5 months before Election Day. People have remarked on the fact that having Trump Jr., Kushner and Manafort all at that meeting meant that basically the entire senior leadership of the campaign as of 6/9/16 was in that one room. The number 3 was actually a significant fraction of the entire campaign staff as of that date.
This consideration leads to our second number that Trump used in that 6/9/16 tweet, 823. He mocks Clinton for having 823 staff in her campaign at the time. The obvious point is the contrast with his own campaign organization on that day, some much smaller number, of which the 3 at the meeting would have been a big chunk. Yet, having heard the report of that 6/9/16 meeting, Trump believed that his piddling small campaign staff had completed that Hail Mary pass. He believed that his campaign would soon be in possession of the incriminating e-mails between her and people at the DNC that would give him an election he had no hope of winning in conventional terms. Her 823 staff was emblematic to Trump of her massive advantage in conventional terms, an advantage his pathetically small staff had just overcome by making a deal for the hacked DNC stuff.
Trump knew about the meeting with Veselnitskaya even before it took place because, at that time, getting his hands on the smoking gun missing e-mails was his leading strategy for winning in November. The 6/9/16 meeting wasn’t some Trump Jr sideshow. It was thought of by Trump himself as the main show, because those lost e-mails hidden in the DNC data dump were going to be his ticket to the White House. Manafort’s presence at the 6/9/16 meeting is telling, as it seems unlikely that he put any great store in this ridiculous idea that the 33k e-mails were deleted to hide a smoking gun that was going to save the campaign, and he would have been wary of the danger of getting anywhere near this material hacked by Russians. Manafort was only there because Trump told him to be there, and to keep Trump Jr from doing anything even more foolish than holding this meeting was all by itself.
And that is, indirectly, exactly how he did win. He never did put together a conventionally effective campaign. He continued to be a walking, talking gaffe generator. Manafort never could get him to pivot. Trump won because the Russian state security services ran a disinformation campaign for him.
There was, of course, no smoking gun e-mail found in that great mound of hacked DNC junk. The axiomatic belief that the 33k e-mails could only have been deleted because their content was criminal in nature, was always a pipe-dream. Nor was there anything else of actual, fact-based, general use in the vast hunk of hacked DNC e-mails. They were mostly about where to eat lunch. If you’re alt.right enough, if you start with the axiomatic belief that DNCers are criminals, even recurring plans to eat pizza at that place near DuPont Circle is proof that something monstrously criminal is afoot, so you drive to the pizza place with a gun to expose the child sex ring. But that degree of crazy is not a big enough demographic to win an election. Not yet, anyway.
However, the disinformation campaign that Russian state security ran for Trump after that 6/9/16 meeting, in exchange for his future repeal of sanctions, probably did deliver him his improbable victory. The micro-targeting of disinformation in key states and counties seems to have had its effect, though it isn’t clear if many individual disinformation messages relied at all on the hacked DNC junk. Russian state security is just good at disinformation, and so can be effective even without smoking gun material to work with. But the last gasp of the “lost e-mails” myth/disinformation may actually have been the decisive blow. The fact that apparently some e-mails between Clinton and Abedin ended up on Weiner’s laptop, and were thought initially to be “lost” emails from among the 33k, is what got Comey to intervene the week before the election.