Rosenstein would tell Trump to pound sand. And then Sessions would remind us that Rosenstein, a fine, upstanding public servant, has his full confidence. Nobody is perfect, after all.
In which case Trump would have transparent legal cause to terminate Rosenstein.
Trump could then nominate someone who obeys the Constitution to be the new D.A.G.
In fact, there is absolutely no reason why Trump can't walk into Mueller's office tomorrow morning, and hand Mueller an Executive Order to turn over the Comey Memos to the news media.
If Mueller refused, Trump could fire Mueller.
What is the news media going to do?
Refuse to publish them at the same moment their editors and film critics are praising the movie about the Washington Post releasing the Pentagon Papers?