Rep. Devin Nunes (R-CA) Brendan Smialowski | AFP | Getty Images

Another Deep State conspiracy theory hyped by President Donald Trump and his Republican allies has withered under scrutiny. In February, it happened with the so-called "Nunes memo" that the White House had hoped would discredit the FBI investigation into connections between Trump campaign advisors and potential Russian agents. The memo, by failing to undermine the basis on which the FBI conducted surveillance, proved to be a dud. On Thursday, the Justice Department inspector general released his report reviewing the FBI's conduct in its 2016 investigation into Hillary Clinton's use of email. Here, too, Trump and his supporters had openly rooted that the findings would back up their claims that the president has been victimized by political bias from entrenched forces within the government that oppose his policies.

The 568-page report by Inspector General Michael Horowitz did not back up their claims. In fact, it showed the opposite. Horowitz criticized, sometimes sharply, the conduct of multiple FBI officials. He said he was "deeply troubled" by text messages exchanged by Peter Strzok and Lisa Page that demonstrated hostility to Trump. With similar communications, three other officials also "brought discredit to themselves," the IG report concluded. The IG concluded that the private views of those officials "created the appearance" that bias had influenced their investigation of Clinton's email practices. He did not conclude that bias actually did influence their investigation. "We did not find documentary or testimonial evidence that improper considerations, including political bias, directly affected the specific investigation decisions," Horowitz wrote. He criticized former Attorney General Loretta Lynch for an "error in judgment" in failing to cut short an airport tarmac conversation with former President Bill Clinton before the Justice Department had concluded the email investigation. But he did not back up Trump's tweeted suggestion that Clinton dangled favors for Lynch in return for going easy on his wife. "We found no evidence that Lynch and former President Clinton discussed the (email) investigation or engaged in other inappropriate discussion during their tarmac meeting," the IG said.

FBI Director James Comey. Getty Images

Horowitz also had sharp words for former FBI Director James Comey, who Trump fired last year. He called it "extraordinary and insubordinate" for Comey to hold a July 2016 press conference explaining the decision not to seek charges against Clinton in the email case. That press conference "deviated from well-established (Justice) in a way intentionally designed to avoid supervision by department leadership," the IG report concluded. It also found Comey made a "serious error in judgment" by telling Congress in late October the FBI was investigating newly-discovered emails, which ultimately proved insignificant in the probe. But Horowitz did not attribute Comey's decision to political bias. Most significantly, he did not fault the decision not to prosecute. "We found no evidence that the conclusions by the prosecutors were affected by bias or other improper considerations," the IG report concluded. "Rather, we determined that they were based on the prosecutors' assessment of the facts, the law, and past Department practice."