Comey has been under fire for almost a year by both Republicans and Democrats since his famous (or infamous, depending on your politics) press conference in which he revealed the FBI's logic (or lack thereof) in not recommending criminal charges against Hillary Clinton, despite finding evidence that Clinton improperly handled, stored, and transmitted highly classified national security information through her private email server in violation of State Department policy.
Since then, Comey has also confirmed the existence of an investigation into members of the Trump campaign for possible collusion with Russian agents.
All of this led to the Inspector General of the Department of Justice opening an investigation into Comey’s conduct in the Clinton case, as it is against Justice Department policy to confirm the existence of ongoing criminal investigations and to take actions or make statements that have the potential to impact our electoral process.
Though Comey claims that he was stuck between a rock and a hard place when it came to public pronouncements on the Clinton investigation, it was still against Justice Department policy to confirm the existence of the investigation into the Trump campaign.
Months later, it was revealed that a dossier containing derogatory information about President Trump that was allegedly collected by a former British Intelligence officer was used in part to justify the investigation into President Trump, though its veracity and the means by which it ended up in the FBI’s possession has been the subject of great debate.
Finally, in the past few days, the veracity of Director Comey’s testimony regarding both the Clinton and Trump investigations has been called into question.
This, along with Comey’s previous questionable conduct over the past year, appears to ultimately have led President Trump to conclude that Director Comey was no longer capable of leading the FBI.
Unless other mitigating information comes to the surface, it appears as though Comey has no one to blame for his firing but himself.