Former president Donald Trump appearing in federal court in Miami on Tuesday, facing 37 criminal counts related to his handling of classified documents, is a sad but necessary moment of truth and accountability. Even for his staunchest opponents, it should be nothing to celebrate.

The facts of the case, as detailed in a 49-page indictment, are deeply disturbing — and extraordinarily dangerous. On leaving office, Trump took “scores of boxes” with him that he was not authorised to possess. They contained highly classified files on, among other things, nuclear programmes, weapons capabilities, US military vulnerabilities and plans for retaliation after a foreign attack. Despite the extreme sensitivity of the files, Trump stashed them haphazardly around his golf club, “including in a ballroom, a bathroom and shower, an office space, his bedroom, and a storage room”. On at least two occasions he showed them off to others. Commenting on a plan of attack, he said, “This is secret information. Look, look at this.”

As the Government tried to intervene, Trump lied and dissembled at every step. When officials from the National Archives and Records Administration demanded the documents, he ignored them for months before turning over a small fraction. When a federal Grand Jury subpoenaed the files, Trump did everything he could to obstruct the inquiry, including asking his lawyer to destroy documents and lie to the Federal Bureau of Investigation; directing an aide to hide evidence; withholding multiple sensitive files; and causing his lawyer to falsely certify that all the required material had been produced. When the FBI finally raided his club last August, agents uncovered 102 classified documents still on the premises.

Unlawfully handling such files is a serious crime. The Justice Department has in recent years prosecuted it aggressively, bringing charges against retired general David Petraeus, former Central Intelligence Agency officer Jerry Chun Shing Lee and former defence contractor Harold Martin, among many others. Earlier this month, former Air Force intelligence officer Robert Birchum was sentenced to three years in prison for conduct remarkably similar to Trump’s. In other words: this is not a case of overzealous prosecution or partisan hardball, as Trump’s allies are claiming.

Nor does the former president deserve the benefit of the doubt. Trump has done business with fraudsters, mobsters and gangsters, and he has legions of former customers who claim they were cheated. By one analysis, he and his firms have been involved in more than 4,000 court cases over the years. His company was recently convicted of 17 criminal charges, while he himself was charged with 34 counts in a hush-money probe and found liable of sexual abuse and defamation in a separate suit. From the start of his term in office, Trump engaged in misconduct so reckless that it tested the limits of presidential immunity. He is still under investigation for attempting to unlawfully retain power, incite a riot at the Capitol and interfere with the 2020 election. No one could argue that he naively blundered into a prosecutorial trap.

For all that, the question of whether Trump’s indictment is justified is separate from whether it is good for the country. He is, after all, a former president and the front-runner for his party’s nomination in 2024. Republicans are already vowing to retaliate against President Joe Biden and his family once he leaves office, thus threatening to engage in the very behaviour they claim to be deploring. Such politically driven prosecutions — something the United States has largely managed to avoid — could weaken American democracy and turn US politics, already grim, uglier still.

Yet the former president’s alleged conduct was so egregious — and the evidence so damning — that in reality prosecutors had little choice but to bring these charges. Civility must at some point yield to the rule of law, the pursuit of justice and the protection of the nation.

• Michael R. Bloomberg is the founder and majority owner of Bloomberg LP, the parent company of Bloomberg News, UN Special Envoy on Climate Ambition and Solutions, and chair of the Defence Innovation Board