You can fire an FBI director without breaking the law, you cannot tamper with witnesses and not break the law. One is by definition a crime.
I can't believe this has to be explained. You are assuming the crime in one case and not the other.
What is witness tampering in the case of Clinton? It's advising people about what to say under oath. You can absolutely tell people what to say under oath and not break the law, for example if you tell them to tell the truth. If you tell them to say something OTHER than the truth in order to impede an investigation you have obstructed justice. Similarly you can fire the FBI director and not break the law, but if you fire him to impede an investigation you have obstructed justice.
You previously and falsely claimed firing the FBI director can't be obstruction of justice. Do you admit this is wrong now?
Looking into obstruction is none the less not an indication that Mueller thinks he has a good case of obstruction.
Whatever you need to tell yourself.
You do not get to decide what is irrelevant.
The law gets to decide what is irrelevant, and the statutes for obstruction of justice are very clear that the attempt is what matters, not if it succeeds. The law and I are both in agreement, it is irrelevant.
There is no good evidence that Trump thought this would end the Russian investigation. Do you think Trump is stupid enough to think Comey was personally the only person running the investigation and it would go away if he just fired Comey? That isn't credible. It is insane.
Of course there is good evidence that Trump thought it would influence the Russia investigation. According to reports that the White House does not even dispute as of last time I checked, he told the Russians that firing Comey would relieve pressure on him related to the Russia investigation.
https://mobile.nytimes.com/2017/05/19/us/politics/trump-russia-comey.html
"I just fired the head of the F.B.I. He was crazy, a real nut job,” Mr. Trump said, according to the document, which was read to The New York Times by an American official. “I faced great pressure because of
Russia. That’s taken off.”
Regardless of whether or not you think he is stupid and/or insane (I agree he appears to be both), from this document he clearly thought it would influence the investigation.
Glad we cleared this all up. Lol. I'm kind of amazed you didn't know this basic stuff.