"No sitting U.S. President has ever tried to pardon his own alleged co-conspirators, so this has never been tested in practice. If Donald Trump were to issue a pardon for Michael Cohen for his actions in the Trump-Russia scandal, the courts would have to rule whether such a pardon is Constitutional, and whether to uphold it or nullify it. From there, Special Counsel Robert Mueller would have to decide whether to charge Trump with obstruction of justice for having tried to use a pardon to prevent an alleged co-conspirator from testifying against him.

So there are three different possible outcomes. Different legal scholars have stated different views on which way they think the court might rule. The key here may be that for a judge to have signed off on a search warrant against him for the seizure of communications between Trump and his attorney, the judge must have believed there was evidence that Trump and Cohen conspired to commit a crime. This would directly paint Trump and Cohen as alleged co-conspirators, perhaps bolstering the legal argument that Trump can’t legally pardon Cohen.

But the bottom line is this: if New York State brings parallel charges against Cohen, then there will be nothing Trump can do, as the president cannot pardon state level charges."


http://www.palmerreport.com/analysis/pardon-michael-cohen-trump-law/9321/