Editor’s Note: Shanlon Wu is a former federal prosecutor and CNN legal analyst. He served as counsel to Attorney General Janet Reno. Follow him @shanlonwu. The views expressed in this commentary are his own. View more opinion at CNN.

CNN  — 

Robert Mueller’s failure to reach a decision about whether President Donald Trump should be prosecuted for obstruction of justice was a mistake that failed both his mission and our country.

This mistake arose not out of corruption, malice, or partisanship, but out of a mistaken sense of modesty. While typically considered a virtue, modesty, like any other virtue, can become a fault when wrongly applied. That is exactly what happened when Mueller chose not to reach a decision about the overwhelming evidence set forth in his report about President Trump’s efforts to obstruct justice. Mueller’s modesty became meekness and it could not have occurred at a worse time for the country.

Shanlon Wu

The special counsel’s meekness apparently arose out of his perception that there was a conflict between two standards used at the Justice Department. The first standard is the Nixon-era opinion by the Department of Justice’s Office of Legal Counsel (“OLC”) prohibiting the indictment or criminal prosecution of a sitting President. The second standard is direction in the Justice Department’s Justice Manual that federal prosecutors assess whether a person’s conduct “constitutes a federal offense.” Mueller’s decision to abide by the first standard but not the second was an exercise of discretion unfounded in any legal principles or rules.

Indeed, he should have followed both standards, because they in no way conflict with each other. Rather, they complement each other by directing a federal prosecutor investigating the President to determine if the conduct at issue was a federal crime but refrain from indicting a sitting President.

But into this seemingly simple two-step process Mueller inserted his own sense of “fairness.”

Specifically, Mueller stated his belief that “fairness concerns counseled against reaching a potential judgment” that the President had committed obstruction of justice because the prohibition against charging the President meant the President could not defend himself against the charge.

But Mueller’s belief relies upon the flawed premise that the only way the President can clear his name is through an actual criminal case. This makes perfect sense if a criminal case is being brought but makes no sense when a criminal case is not brought. If a criminal case is not brought, the President would be free to respond any way he wished – through a rebuttal prepared with the aid of counsel and/or in the court of public opinion through social media (e.g., Twitter), the White House press secretary and other advocates. Given that, that is exactly what is happening, and it is obvious that Mueller’s solution accomplished nothing different than if he had announced a determination that the President engaged in criminal conduct but would not be charged.

Indeed, Mueller’s actions make it plain that he must have concluded that the President committed obstruction of justice because he otherwise would have announced, as he did with regard to his Volume I conclusions, that the evidence did not establish obstruction of justice. Mueller thus inconsistently chose to follow the Justice Manual direction about collusion/conspiracy but not about obstruction.

Why did Mueller act in this illogical and inconsistent manner? Let me postulate that Mueller suffered from an attack of modesty. Having lived and thrived for years in the political minefields of Washington, DC – it was his second nature to avoid situations where he might be accused of grandstanding or overreach. A decision to announce that the President of the United States had committed a crime but would not be charged would have placed him front and center at one of the most controversial decisions of the modern political era.

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    I think Mueller did not want that to be his legacy. Instead he wanted a legacy of having run a tight ship, and delivered his investigation in a timely, professional fashion. He accomplished that but failed at the very mission for which he was appointed, namely, to have a non-politically appointed prosecutor decide whether the President had engaged in criminal conduct. By modestly leaving that decision to perhaps the attorney general and/or perhaps Congress, he missed the forest for the trees.