Josh Campbell is a CNN law enforcement analyst, providing insight on crime, justice and national security issues. He previously was a supervisory special agent with the FBI. Follow him on Twitter at @joshscampbell . The views expressed in this commentary are his own.

(CNN) In today's polarized political climate, it is fascinating, but not surprising, that a group of detractors would start early in their attempts to discredit a new memoir by former FBI Director James Comey before they have even read it.

Fascinating, because of the sheer number of amateur armchair prosecutors who have come out of the woodwork to clamor for public attention and wax poetic about investigations in which they had no part. Unsurprising, because we are sadly now in a post-truth world where drawing conclusions without having the full facts is commonplace.

The Republican National Committee, for one, is going all-in as part of a new campaign to destroy Comey's credibility and reputation before his book's release. The "party of law enforcement" is now using its precious resources to attack the former head of the nation's premiere law enforcement agency. Let that sink in.

As a former FBI special agent who also served a stint as Comey's special assistant, I saw firsthand how partisans on both sides of the aisle tended to either champion or denounce the former director depending on whose political ox seemed to be gored on a given day.

I saw the hypocrisy from politicians and others who on one day would gush about being fans of his and appear to relish the Comey good housekeeping stamp of approval if his actions appeared to be in their favor, and then on the next day would publicly ridicule him and treat him as the devil incarnate.

The pre-emptive efforts to criticize Comey's memoir have their roots in the unfortunate politicization of the FBI that we've seen over the past year. Our precious institutions of justice were once off limits to the antics of political operatives, but the destruction of norms has now made way for open season on the FBI.

It is my judgment, and that of many of my former FBI colleagues currently on the job, that Comey was fired largely in an effort to thwart the FBI's Russia investigation.

At the time, the White House indicated Comey was fired based on a memo, which was drafted by stooges at the Justice Department, ridiculing Comey's handling of the Clinton investigation. However, President Donald Trump would later allude to the Russia investigation as his motive for the termination.

The Clinton pretext was nearly brilliant because it presented a red herring while simultaneously riling up many in the Republican base who, to this day, remain upset that Comey recommended against prosecuting Hillary Clinton.

Once sidelined, the campaign against Comey shifted to special counsel Robert Mueller and his team, after it became clear the FBI's investigation into possible collusion was not going away. Fearful of where it might lead, those operating in survival mode have launched nothing short of a full-court press to denigrate Mueller.

This has included attacks by both the White House and Congress. If these political operatives are able to discredit those doing the investigating, their thinking goes, they just might convince a segment of society that the results of the investigation are also flawed.

To be fair, I have no doubt there are smart and well-intentioned people who genuinely have questions about the actions of the FBI. Occurrences like the disgraceful and politically charged text messages between FBI officials Lisa Page and Peter Strzok, which were released devoid of any context, and the summary dismissal of former FBI Deputy Director Andrew McCabe without any specific details from the Department of Justice, have provided fodder for those seeking to discredit the FBI.

And Comey has much to explain about decisions and actions made over the past two years, including his decision to reopen the Clinton investigation before the election, his handling of the personal notes he made after his meetings with the President, and White House efforts to influence the direction of an FBI investigation.

However, his biggest hurdle with the new book will be changing the minds of those who have fallen victim to the campaign to manipulate public opinion and besmirch his reputation. To reach the public, he will need to squelch the political noise from operatives at the RNC and critical pundits who ridicule him for finally giving us his side of the story, while they hypocritically get paid each day to give us theirs.

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Although I haven't read the book, I'm confident it will take the public along with him and describe the many political landmines he had to navigate in countering outside influence on the FBI. As someone who worked alongside him and saw the countless difficult decisions he had to make during unprecedented times, I'm confident an open-minded public will understand his decisions, even if they don't fully agree with them.

The Comey I knew ignored all the partisan noise and clamor, and simply conducted himself in a manner consistent with the rule of law. Time and again I saw him making hard leadership decisions that were nearly universally detrimental to him personally, but in the best interest of our vital institutions of justice.