This is fake news and shame on Memeorandum for giving it momentum. The text of the story should tip off everyone that it is fake news. The “supremacy clause” has nothing to do with whether or not a sitting President can be indicted.
Also, if you go down the rabbit hole, the claim is that the FISA court issued the indictment and the FISA court does not issue indictments at all.
I am amazed to see supposedly rational, sane people now breathlessly spreading this stuff around. Trump Derangement Syndrome is a real thing and Russia-ism really is the new birtherism.