'It's never taken me 400 pages to say nothing happened': Former US Attorney thinks Mueller found something

Word is, the complete report from special counsel Robert Mueller is 400 pages long. There's been previous reports it was closer to 700 pages and over 300 pages, but regardless of how many hundreds of pages, one former U.S. Attorney said it's indicative that Mueller found something.

In a Monday discussion with MSNBC's Nicolle Wallace, Chuck Rosenberg explained why he thinks there's more in the report than people think.

"It's never taken 400 pages for me to say nothing happened," he said. "So, I imagine something happened, I imagine that something, particularly with respect to obstruction was quite serious."

He said that one theory behind Mueller's decision not to recommend prosecution for obstruction is all about the Justice Department's procedures and policies.

"The Department of Justice has in place policies one dates to the '70s, one dates to 2000, to say to charge a sitting president would be overly burdensome, would stigmatize the presidency. So, we just don't charge sitting presidents. With that in mind, even if the obstruction constituted a crime, and it may well have, we don't know that yet, I can imagine Mueller not making a recommendation because a recommendation to prosecute someone you can't prosecute is equally burdensome and equally stigmatizing."

Wallace wondered why Mueller then wouldn't do what's called a declination decision. Rosenberg explained that the fact wouldn't support it.

"I don't believe for a minute, if Mueller had facts that exonerated the president on obstruction, he would have hesitated to say so," he said, noting that the fact Mueller couldn't exonerate him was telling.

Watch the full discussion below: