Story highlights Tim Naftali: Trump not first to fire an FBI director, but first to do it while director running probe into President's campaign

He says timing of the firing ensures that the Russia hacking scandal is not just going to melt away

The former director of the Richard Nixon library, Timothy Naftali is a CNN presidential historian who teaches history and public policy at NYU. The views expressed in this commentary are solely his.

(CNN) James Comey was the one man that both Hillary Clinton and Donald Trump would likely have wanted to fire during the 2016 campaign. Now that one of them has done it, it may be a decision the President will regret.

Tim Naftali

Comey's dismissal is an earthquake not because Donald Trump is the first President to fire an FBI director (he isn't). As former FBI director (and federal judge) William Sessions told me in an interview over a decade ago, President Bill Clinton made clear he wanted Sessions fired after assuming office in 1993.

After the Clinton White House failed in its efforts to encourage him to leave, in July 1993, Clinton announced that at the request of Attorney General Reno, he was dismissing Sessions , citing a negative report on Sessions from the Department of Justice's Office of Professional Responsibility.

No, today's firing is a big deal because, unlike in 1993, the President is pulling the plug on an FBI director as the bureau is in the midst of a high-profile investigation involving the new President's former campaign team and a foreign power.

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Comey has a lot of enemies in Washington, DC and the President and Attorney General Jeff Sessions may well have viewed his recent error-filled testimony -- in which he misstated by a huge order of magnitude the number of Hillary Clinton emails Huma Abedin had forwarded to her husband, Anthony Wiener -- as the cover they were looking for to fire him at minimal political cost.