The Mueller report makes it clear that, as many people have said all along, “collusion” is neither a legal term nor a charge that could be investigated. Instead, it explicitly states “the Office’s focus in analyzing questions of joint criminal liability was on conspiracy as defined in federal law.”
Even on the term “cooperated,” the fragment that Barr used didn’t mean that term in the way most people would understand it, but only in the sense of an actual agreement between two parties to work together in some formal way.
That requires more than the two parties taking actions that were informed by or responsive to to the other’s actions and interests.
The Mueller report explicitly says that Trump’s team had multiple contacts with Russia, and that those contacts included the exchange of information with expectations that it would help the campaign. It only failed to meet the level of criminal conspiracy because there appears to have been no formal agreement of cooperation.
That’s worlds apart—and words apart—from the way Barr used that sentence.
That’s collusion. Collusion. And, dammit, collusion. Also cooperation, in the sense that everyone else uses it. This report is damning for Trump, damning for his campaign, and utterly damning for Barr.