Trump is the one who hired Deputy Attorney General Rod Rosenstein.

Session recommended him. That's actually another strike against Sessions.

It is Rosenstein whose order appointing Robert Mueller fails to set limits on Mueller’s investigative jurisdiction, thereby authorizing the fishing expedition that has Trump so ballistic.

It's pretty clear that Rosenstein is part of the witch hunt. He's a Dem agent that Trump can't really fire because Session recused himself. Trump relied on Sessions judgement and he got burned.

Moreover, it was Trump’s own botching of the firing of FBI director James Comey that spooked Rosenstein, inducing him to appease furious Democrats by giving Mueller free rein.

Rosenstein was interviewing Mueller the day before Comey was fired. Trump fried Comey because he identified him as the primary leaker in the FBI and you'll note that Trump induced Comey to prove he was a leaker by admitting to it under oath. Which of course was negated when Mueller gave Comey immunity. The deepstate protects it's own.