Lawrence O'Donnell is no more "News" than Sean Hannity. Both are "columnists" meaning they can say whatever they want. It does not excuse getting this story wrong or at least premature.
When somebody presents something as news, though, it should be real and vetted. Neither O'Donnell nor his "source" have ever seen the documents in question, and NBC News couldn't verify the story. Rachel Maddow obviously knew this was coming, as well. None of them cared before going to air with this.
We've seen media across the spectrum be careless and/or intentionally misleading with stories. I don't know what the answer is. A "free press" should be free from government interference, but should it be free to publish lies?
Should the President be free to publish lies?
Like what carries more weight:
"Some people are saying..."
"I have a confirmed source within a bank who has seen the information"
Trump was the master of this: he tweeted that he had "inside information which proves Obama wasn't born in Hawaii". That turned out to be false. Nothing EVER said to retract, water down, or walk back the remarks.
Conversely, you have a journalist admitting that he hasn't followed guidelines (presumably they need to see hard evidence, rather than just talking to a staffer who claims to have seen something), apologising, and offering to make a very embarrassing and public climb down on national television...
Trump has some many people hoodwinked on this fake news **** it's depressing.
I actually quite like many aspects of Trump's foreign policy, and I can understand why a lot of people like his policies. But this inability of his supporters to see this one truly dangerous thing he is doing is mind-blowing.