Even more lethally, the trove included extracts from Clinton’s lucrative speeches to banking groups. In one of those speeches—sponsored by a Brazilian bank—Clinton expressed her hope for a “hemispheric common market, with open trade and open borders, sometime in the future, with energy that is as green and sustainable as we can get it, powering growth and opportunity for every person in the hemisphere.” In another speech in the trove, Clinton suggested that many politicians hold “both a public and a private position” on contentious issues—implying that public words cannot be trusted.

The huge dump took a while to be analyzed and absorbed. It did not immediately displace the salacious Access Hollywood story from the top of the news.

But by the second week of October, WikiLeaks was profoundly engaging the U.S. voting public. Using the Google Trends tool, the website Five Thirty Eight tracked how public interest in the hacked emails surged. Not coincidentally, it seems, Clinton’s poll lead over Trump peaked on October 17, and steadily shrank thereafter. FBI Director James Comey’s October 28 letter reopening the Clinton email case delivered the final blow to the reeling Clinton campaign.

This timeline is one thing to keep in mind as details emerge from the Mueller report.

Read: Imagining Trump’s America without Robert Mueller

It’s not a theory but a matter of historical record that Vladimir Putin’s Russia hacked American emails and used them to help elect Trump to the presidency.

It’s not a theory but a matter of historical record that agents purporting to represent Putin’s Russia approached the Trump campaign to ask whether help would be welcome, to which Donald Trump Jr. replied, “If it’s what you say I love it especially later in the summer.”

It’s not a theory but a matter of historical record that Donald Trump publicly welcomed this help: “I love WikiLeaks!”

It’s solid political science that this help from Russia via WikiLeaks was crucial, possibly decisive, toTrump’s success in the Electoral College in November 2016.

Mueller was asked to investigate how much the Trump campaign knew in advance about this Russian help. Along the way, the special counsel also apparently became interested in the question of why Putin was so eager for a Trump presidency. Did Putin have some kind of prior hold over Trump, financial or otherwise?

For two years, Americans and the world have speculated and argued about the inquiry. But along the way, we have often lost sight of the core truth of the Trump presidency: For all its many dark secrets, there have never been any real mysteries about the Trump-Russia story.

Read: What Mueller leaves behind

The president of the United States was helped into his job by clandestine Russian attacks on the American political process. That core truth is surrounded by other disturbing probabilities, such as the likelihood that Putin even now is exerting leverage over Trump in some way.