Before the WaPo wrote this, the Bitemaster was saying the same thing (you’ll have to trust me). The way I figure it, it was a win-win for the Ruskies. Either they could turn some of Trumps inner circle, or compromise them so they could be blackmailed later.
When Donald Jr. released his emails, he precluded any Russian blackmail attempt. I thought it was a smart move on his part.