It is this
"Barr added that after review, he and Deputy Attorney General Rob Rosenstein "have concluded that the evidence developed during the Special Counsel's investigation is not sufficient to establish that the President committed an obstruction-of-justice offense."
So this could mean anything within that limit.
There was no evidence of collusion, none, and that was why the entire thing started in the first place. No evidence means that the FISA warrants were obtained by false evidence.
Obstruction of justice is a high bar to reach, and is complicated. We know that Trump never invoked executive privilege which the previous three presidents did. We know that Mueller never complained about not receiving documents he wanted, and many hundreds of thousands of pages were shared by the White House.
Obstruction of Justice is based upon criminal intent. Knowing that what you are doing is clearly understood as a criminal act.
The Justice Department has reviewed the entire Mueller report, and has determined that there is insufficient to make a case.
Insufficient most likely means means that the element of criminal intent is not present.
Democrat hitters like Schiff and Knadler have, for two years, insisted that there was a plethora of evidence to prove collusion by Trump and his campaign with the Russians.
They are sewer dwelling bald faced liars. 2 years, 25 million dollars, 17 full time lawyers, a large number of investigators. 500 witnesses interviewed, hundreds of search warrants served all make their lies hugely apparent.