WASHINGTON — To charge a criminal conspiracy between the Trump campaign and Russia, Robert Mueller decided he had to prove the existence of an explicit, corrupt agreement between the two sides. It wasn't enough, his report said, that the Trump campaign and Russia were acting out of mutual interest.

Mueller said he didn't find a conspiracy he could prove. But he did establish in painstaking detail that the Russians and the Trump campaign pursued a relationship of mutual benefit during the election campaign — and afterward.

Some might argue that verges on a different sort of collusion.

"The report reveals that there was an awful lot of contact between people in Trump world and Russians, and there appears to be at least some attempt at coordination," said Greg Brower, a former U.S. attorney during the George W. Bush administration and senior FBI official. "One could argue you put all that together, it looks like collusion."

The report says, "The investigation did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities."

But it also says that "the investigation established that the Russian government perceived it would benefit from a Trump presidency and worked to secure that outcome, and that the campaign expected it would benefit electorally from information stolen and released through Russian efforts."

And after the Russians helped Trump get elected though efforts that were apparent to the Trump campaign, the report says, the Russians reached out to members of the Trump transition team, including the president's son-in-law, ostensibly seeking the fruits of their labors. After a backchannel meeting in the Seychelles, the head of Russia's sovereign wealth fund passed a friend of the president's son-in-law a two-page document proposing how the Trump administration could promote "U.S.-Russia reconciliation."

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Two days before Trump took office, the document found its way to Jared Kushner, who promptly passed it along to incoming White House adviser Steve Bannon and incoming Secretary of State Rex Tillerson.

The Mueller report is "a damning account of a wildly successful Russian influence operation from start to finish," said Clint Watts, a former FBI agent and social media expert. "The Russian approach was, 'Let's reset foreign policy relations with the United States in a way that we're getting everything we want,' and they were pursuing that on multiple fronts."

In Volume I of Mueller's 448-page report, Mueller details a bevy of contacts between the Trump campaign and Russia. One of the amazing things about it is that the vast majority of them had already been extensively explored by the news media. That included the June 2016 Trump Tower meeting, set up on the promise that a Russian lawyer would hands the campaign incriminating information about Hillary Clinton.

Yet there are many new details and some new incidents. There was a second offer of help from the Russians "to provide negative information about candidate Clinton to the Trump Campaign," the report says, but the particulars are redacted because the matter remains under investigation. That may or may not relate to something that happened with Trump associate Roger Stone, who was absent from the report because he has been accused of lying to the FBI and the case is still pending.

"The Russian contacts consisted of business connections, offers of assistance to the campaign, invitations for candidate Trump and Putin to meet in person, invitations for campaign officials and representatives of the Russian government to meet, and policy positions seeking improved U.S.-Russian relations," the Mueller report says.

Many are well known by now: Michael Cohen's interactions with Vladimir Putin's office over a Trump Tower in Moscow. George Papadopoulos, who told the Greek foreign minister the Russians had Clinton's emails, sought to broker a meeting between Trump and Russian president Vladimir Putin.

On Aug. 2, 2016, the report says, Trump campaign chairman Paul Manafort met in New York City with his long-time business associate Konstantin Kilimnik, a man the FBI believes is a Russian intelligence operative. Kilimnik sought the meeting to deliver a peace plan for Ukraine — one that Manafort later acknowledged would have allowed Russia to control part of eastern Ukraine.

"They also discussed the status of the Trump Campaign and Manafort's strategy for winning Democratic votes in Midwestern states," the report says. Months before, Manafort "had caused internal polling data to be shared with Kilimnik, and the sharing continued for some period of time after their August meeting."

Mueller doesn’t say what Kilimnik did with the polling data, but experts have said it could have been used to help the Russian election interference effort.

And then: "Immediately after the November 8 election, Russian government officials and prominent Russian businessmen began trying to make inroads into the new administration. The most senior levels of the Russian government encouraged these efforts. The Russian Embassy made contact hours after the election to congratulate the President-Elect and to arrange a call with President Putin. Several Russian businessmen picked up the effort from there."

After that came the famous phone calls between National Security Adviser Mike Flynn and the Russian ambassador, lies about which led to Flynn's downfall.

The report makes no comment on the propriety of those contacts and meetings — in stark contrast to former FBI Director James Comey accusing Hillary Clinton of "extremely careless" conduct when he announced in July 2016 that he recommended no criminal charges in the case over her email.

But foreign policy experts and campaign veterans have said, over and over during the 22-month investigation, that it was not normal — and in fact was deeply suspicious — for a presidential campaign to foment a secret relationship with a major U.S. adversary.

That relationship and the actions Trump took to conceal it posed such a concern that the FBI opened a counterintelligence investigation, former Acting FBI Director Andrew McCabe testified.

There is no mention of that in the Mueller report. In fact, the word "counterintelligence" appears just eight times, all in pro forma fashion. The report does not say anything about financial ties, if any, between Donald Trump and Russia, or blackmail, or any other source of compromise.

Current and former intelligence officials say that Mueller does in fact have counterintelligence findings, but they are classified. The House Intelligence Committee has asked for a briefing on them, and so far has not received one.

"After a 17-month investigation, testimony from some 500 witnesses, the issuance of 2,800 subpoenas, the execution of nearly 500 search warrants, early morning raids, the examination of more than 1.4 million pages of documents, and the unprecedented cooperation of the President, it is clear there was no criminal wrongdoing," Trump's legal team said in a statement.

Whether or not that is clear, that is not the only standard to which a president is held, and Democrats in Congress plan to continue investigating.

"Whether obstruction was criminal or not, whether these contacts were sufficiently illicit — they are unquestionably dishonest, unethical, immoral, unpatriotic," said Adam Schiff, D-Calif., the chairman of the House Intelligence Committee. "They should be condemned by all Americans."