If a sitting president sends a public message to his Attorney General telling him he should personally intervene to stop federal criminal investigation into his potential criminal behavior, he is attempting to obstruct justice.
That this needs spelling out is a testament to the bizarre time we are living in, but here is the actual legal definition (via Cornell Law School, bold emphasis ours):
Obstruction of justice is defined in the omnibus clause of 18 U.S.C. § 1503, which provides that "whoever . . . . corruptly or by threats or force, or by any threatening letter or communication, influences, obstructs, or impedes, or endeavors to influence, obstruct, or impede, the due administration of justice, shall be (guilty of an offense)." Persons are charged under this statute based on allegations that a defendant intended to intefere with an official proceeding, by doing things such as destroying evidence, or intefering with the duties of jurors or court officers.
A person obstructs justice when they have a specific intent to obstruct or interfere with a judicial proceeding. For a person to be convicted of obstructing justice, they must not only have the specific intent to obstruct the proceeding, but the person must know (1) that a proceeding was actually pending at the time; and (2) there must be a nexus between the defendant’s endeavor to obstruct justice and the proceeding, and the defendant must have knowledge of this nexus.
And here is what the president tweeted out earlier this week:
When Trump says Sessions "should stop this Rigged Witch Hunt right now" he is quite clearly endeavoring to influence and impede the Mueller probe. He is showing specific intent to obstruct or interfere with an ongoing judicial proceeding, and the tweet was sent out to his 53.4 million followers and picked up by every media outlet in America. It isn't as if we can't see what he is doing -- the president is attempting to obstruct justice in front of the entire nation. In response to Trump's violation of the law, his bumbling lawyer Rudy Giuliani told the press that Trump wasn't trying to obstruct justice because he didn't issue a presidential directive. "He used a medium he uses for opinions, Twitter," said Giuliani. "One of the good things about using that, he's established a clear sort of practice now that he expresses his opinions on Twitter." "He used the word 'should,' he didn't use the word 'must,'" Giuliani went on. "And there was no presidential directive that followed it. He didn't direct him to do it and he’s not going to direct him to do it." https://www.youtube.com/watch?time_continue=3&v=lTXplrP8ojk White House Press Secretary Sarah Huckabee Sanders also echoed this sentiment, telling the media that the president was merely "fighting back". "The president is not obstructing," Sanders said. "He's fighting back. The president has stated his opinion, he's stating it clearly. He is certainly expressing the frustration he has with the level of corruption that we've seen from people like James Comey, Peter Strzok, Andrew McCabe." So there you have it, Trump -- a sitting president -- isn't attempting to obstruct, influence, or impede justice into a criminal investigation into his wrong doing despite clearly doing so on Twitter because he didn't order a presidential directive. In that case, the words "influence," "obstruct," and "impede," must be removed completely from the clause of 18 U.S.C. § 1503, because Giuliani's interpretation of them don't corroborate with what the rest of the English language speaking population believe they mean. According to Giuliani, "influence" must actually mean "demand", and "impede" must really mean "issue a legally binding directive". This Orwellian game Giuliani is playing cannot go on forever -- from fake transcripts to redefining the English language, Giuliani is attempting to tell the public that what they are seeing and hearing with their own eyes and ears is not what is actually happening. That Trump didn't say what he said and didn't mean it either, that he cannot be held to any standards of honesty and integrity because Hillary Clinton/Barack Obama/The Deep State etc, etc, etc. This assault on reality is creating havoc in American society, ripping apart universal truths and destroying objectivity. The Trump administration is counting on the fact that the country will simply give up and determine that they no longer know what is real, but that cannot ever happen. If you attempt to obstruct justice, you must be held accountable for your crimes. Come November it will be time to make Trump and his cronies pay for this, and the cost must be extremely dear.