Directly from the statement today, "The order appointing the special counsel authorized us to investigate actions that could obstruct the investigation. And we conducted that investigation and we kept the office of the acting attorney general apprised of the progress of our work. And as set forth in the report after that investigation, if we had had confidence that the president clearly did not commit a crime, we would have said so. We did not, however, make a determination as to whether the president did commit a crime. The introduction to the volume two of our report explains that decision. It explains that under long-standing department policy, a president cannot be charged with a federal crime while he is in office. That is unconstitutional. Even if the charge is kept under seal and hidden from public view, that too is prohibited. The special counsel's office is part of the Department of Justice and by regulation it was bound by that department policy. Charging the president with a crime was, therefore, not an option we could consider."
Mueller said today the only reason they didn't charge him was because they couldn't. Just like he said in the report at the time.
Read it yourself man.
No American was charged for obstruction because the President is the one who committed obstruction of justice and he cannot be charged.