The astonishing and entirely new fact revealed last week is that, according to Mueller, Manafort, while chairman of the Trump campaign, sent polling data to a Russian associate with close ties to Russian intelligence. The White House in winter. Credit:Bloomberg Until now, Mueller's investigation and reporting by the news media have established two things: that Russian intelligence actively tried to influence the outcome of the election, and that Russian intelligence used numerous pathways to reach out to members of the Trump campaign and inner circle. Lacking so far is any direct proof that the Trump campaign took up these overtures in a way that actively constituted cooperation or collusion. If it can be substantiated - and Mueller almost certainly wouldn't be alleging it if it couldn't - the Manafort revelation is that proof. This cooperation with Russia didn't come from some minor figure in the campaign, but from the chairman himself. This is a hugely significant development.

Sharing campaign research in the form of proprietary polling data has one obvious explanation: Manafort was giving the Russians data they could use to try to influence the campaign. Loading Replay Replay video Play video Play video Proof that the Trump campaign cooperated with the Russians would close the evidentiary circle by connecting Russian outreach with Russian efforts to use social media to affect the vote. Proof that Manafort sent data to the Russians would not be just a step toward proof of collusion. It would itself be proof of collusion. Yet this development, which should have dominated the news cycle, fell distantly behind the topics of the government shutdown, Trump's prime-time address on border security, and the president's threat to invoke emergency powers to build the Mexican border wall that Congress has denied him. Why did the Manafort news get so little attention? Several factors probably contributed.

One explanation is that the revelation didn't come from prosecutors or from leaks to a news organisation. Instead, the information was unintentionally revealed by Manafort's lawyers when they failed to successfully redact a document they submitted to court in connection with Manafort's sentencing. Loading This strange mechanism of hitting the news made the original story one about cutting and pasting a word-processing document, not about the content of what was revealed. A second explanation is that the news media and the public had already given up on Manafort as a source of meaningful Trump-related revelations. After all, Manafort pleaded guilty to a series of crimes that long predated his involvement with the Trump campaign. And based on the length of the sentence Manafort got and prosecutors' insistence that he was still lying even after agreeing to cooperate, many of us had begun to think that Manafort wasn't going to be the subject of any major campaign-related breakthroughs. In retrospect, that conclusion seems to have been premature - maybe even spectacularly wrong. Mueller, it would seem, can prove that Manafort brought the Trump campaign into cooperation with Russia.

The third and most troubling possibility is that, as the Mueller investigation has proceeded, fatigue and acceptance have set in. Trump's supporters and opponents alike may have more or less come to think that there was some sort of collusion with Russia. The supporters, arguably, don't much care. The opponents increasingly think that no matter what Mueller finds, it won't be enough to convict and remove Trump from office in impeachment proceedings. Loading The upshot would be that Mueller's report could turn out to be a kind of historical afterthought - even if Mueller is able to demonstrate collusion between the Trump campaign and Russia, the central component of his mission. Sure, the Democratic House would hold hearings. Some members of Congress would call for impeachment. But if Republicans held firm, many Democrats would probably decide not to impeach because of the unlikelihood of success. In that scenario, it's possible to imagine that even if Trump was aware of the Russian collusion, his supporters would maintain that the Russian efforts had no impact, and that Trump had no idea the cooperation with Russia was irregular, let alone illegal.