Julia Ioffe of The Atlantic seems to have succeeded in convincing the world that WikiLeaks was, and admitted to being, "pro-Trump, pro-Russia."
Her article is based on a series of Twitter direct messages between a WikiLeaks account and Donald Trump Jr., messages that had been leaked to Ioffe and also are in the hands of congressional investigators. They show the WikiLeaks folks both giving information to and requesting information from Trump Jr. (though both parties often ignore each other, and clearly give nothing beyond what would clearly benefit their own interests).
At one point, the WikiLeaks account asks Trump Jr. basically to leak them things that might harm Trump himself: some of his tax returns. Why would Jr. want to do that? WikiLeaks suggests: "That means that the vast amount of stuff that we are publishing on Clinton will have much higher impact, because it won't be perceived as coming from a 'pro-Trump' 'pro-Russia' source."
Ioffe quotes it as above, with a period, as if that's the end of the sentence.
But after the article appeared, Trump Jr. released via Twitter what he claims is the full correspondence himself. Here's the full sentence:
That means that the vast amount of stuff that we are publishing on Clinton will have much higher impact, because it won't be perceived as coming from a 'pro-Trump' 'pro-Russia' source, which the Clinton campaign is constantly slandering us with. [emphasis added by me]
The actual meaning and purpose of the exchanges with Donald Jr. remain at least somewhat open to interpretation. Ioffe and her supporters doubtless believe that the very existence of any of these exchanges is proof that that last clause is self-serving and untrue. But if you are not starting from Ioffe's presumptions, you could easily read what WikiLeaks is doing as a rather transparent attempt to trick someone they think is sort of dumb (Donald Trump Jr.) into leaking things to them.
I'm not saying that's the only reasonable interpretation. But Ioffe committed journalistic malpractice by not quoting the full sentence and thus ensuring her interpretation ruled in readers' minds.
Caitlin Johnstone, who in an article at Medium was the first person I saw pointing out what Ioffe did with that cut-off quote, nicely sums up both what Ioffe has succeeded in doing and a reasonable alternate explanation for WikiLeaks's behavior:
WikiLeaks comes off looking weird and sleazy in a way that will likely damage its reputation even further than the mainstream media campaign to smear the outlet already has. WikiLeaks is seen asking for favors Trump never fulfilled, making recommendations Trump Jr. didn't act upon, and asking for leaks Trump Jr. never gave them, which when you step back and think about it are actually fairly normal things for a leak outlet to do, all things considered.
Bonus link: Vox, a source decidedly not sympathetic to Julian Assange or WikiLeaks, explained before the election some of the obvious and non-sinister reasons why WikiLeaks would have a hard time with Hillary Clinton regardless of whether it's pro-Russia or pro-Trump.