Barr says if a crime wasn't found to have been committed, then there was not obstruction, however...

recused himself on the grounds of not being able to correctly apply the law.

For example, if the obstruction was that the person destroyed evidence that was needed to prove a crime, they couldn't be convicted. Therefore, a criminal would have nothing to lose by destroying evidence because if he was successful, they couldn't convict him of the crime and therefore, the obstruction.

That is not how it works for obvious reasons.

In Trump's case, there was evidence of a crime. Just read the media reports that remain unchallenged or the facts in the indictments and guilty pleas. Trump could well have obstructed Mueller from finding the evidence Mueller needed to prove conspiracy beyond a reasonable doubt. If there was absolutely no evidence a conspiracy took place, Mueller would not have been asked to look into it. He has better things to do. From what I've seen in the media, there may not have been evidence to prove it beyond a reasonable doubt but it sure looked like they could meet the civil standard of the preponderance of the evidence for conspiracy. The campaign manager giving the Russians the campaign's data might be enough right there along with all the indictments of Russians.

Because there was evidence a potential crime was committed - enough that it justified a special counsel of Mueller's stature to look into it - that is ample to cite as a basis for obstruction.

Then Mueller would move to examine if obstruction took place. And he left it for congress to decide as he should. Barr should not have made the decision.

Having consulted with Mueller and Rosenstein... Barr isn't going to hang his ass out to dry in the Dumpster crap storm....he knows how to not be a Cohen or Avenatti