he can fire him and under normal circumstances, doing so would be a P.R. nightmare a la Nixon. But with this joker, nothing touches him no matter how insane.

Edit to add this additional info -

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It is sometimes assumed that the President can oust an FBI director only “for cause” – that is, for some misconduct in office. But, as a Congressional Research Service study of the director’s office pointed out two years ago, “there are no statutory conditions on the President’s authority to remove the FBI director.”

The constitutional reality is that, if a government official is clearly placed within the Executive Branch, that official serves at the pleasure of the President, and can be fired “at will.” That history has had a recent illustration: earlier this month, the federal appeals court in Washington, D.C., struck down part of a law by which Congress created a single director to lead the Consumer Finance Protection Bureau – a law that specified that the director could be removed by the President only “for cause.”

The appeals court simply deleted that phrase from the law, thus making the agency’s head subject to being fired by the President for any reason, or no reason at all. (The government has not yet indicated whether it will challenge that ruling in further appeals, perhaps to the Supreme Court.)

That is very much in line with what the Supreme Court has ruled over the years, to preserve the power of the President to be fully in charge of the Executive Branch. Since 1968, a federal law has provided that the head of the FBI will have a 10-year term in office. But the situation legally is that the chance to serve a full term depends upon retaining the confidence of the President.

http://blog.constitutioncenter.org/2016/10/how-independent-is-the-fbis-director/