Mueller knew there was no collusion within the 1st month of his investigation but kept ‘investigating’ in hope’s that Trump would do something he could cite as obstruction. That’s the reason for the leaks about indicting his son and for the outrageous pre-dawn raids on Manifort and Roger Stone. He was daring Trump to try and stop him. Trump wanted to but he didn’t take the bait.
Speaking of obstruction:
“The obstruction portion of the Report was even less impressive. It advances a broad definitional theory of obstruction that takes eight pages to explain – one that is clearly set up as a response to Bill Barr’s memo on the subject – that I’d love to see a single elected official explain coherently. There’s much fun to be had in counting the footnotes that are Tweets, public interviews, and press conferences. As Rick Klein notes, the Report is more about making a political case against the president than a legal one. And that’s very much how it reads.”