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"O, what portents are these?" demands a deceptively observant character in "Henry IV." Former President Donald Trump must be wondering much the same, after FBI agents searched his home at Mar-a-Lago on Monday. The rest of the country could use some answers, too.

Trump himself first detailed the raid on social media. "Nothing like this has ever happened to a president of the United States before," he said, accurately. "After working and cooperating with the relevant government agencies, this unannounced raid on my home was not necessary or appropriate," he continued. Characteristically, he then seemed to reveal more than intended: "They even broke into my safe!"

The contents of that safe — and the boxes FBI agents were seen removing from the residence — may well prove explosive. Any such search would've required a federal agent to present an application to a judge under oath showing probable cause that there was evidence of a crime on the premises. The judge would've had to agree. FBI Director Christopher Wray, a Trump appointee, and the highest levels of the Justice Department, likely including Attorney General Merrick Garland, would've had to sign off. Everyone involved must have grasped the gravity of what was about to unfold.

According to several news reports, the probe involves the former president's mishandling of classified documents. For the sake of the country one hopes there's more to the story than that. Although Trump was notoriously careless with sensitive information, the Justice Department almost never prosecutes such crimes absent some complicating factor. To do so against a former president, without strong evidence of obstruction or other serious misconduct, would show atrocious judgment — especially since the commander-in-chief is (to simplify slightly) the ultimate determinant of a document's classification status.

It bears emphasizing that this is a fateful moment for American democracy. Whatever happens next, wherever this investigation leads, there can be no unringing the bell. An FBI raid of the former president's house will have shattered norms, created unnerving precedents and upended politics in ways that are impossible to predict. Trump's supporters — including many in Congress — are already seething with rage and seized with conspiracies. A more combustible situation is hard to imagine.

A sober explanation for these actions is thus essential. So far, both the Justice Department and the FBI have declined to comment. A White House spokesman said President Joe Biden knew nothing of the search in advance. Even accepting that open investigations require some degree of secrecy, such silence can't last. The Justice Department must level with the public about the broad contours of this probe and divulge why such aggressive action was necessary.

The sheer amount of unpunished wrongdoing that occurred under the Trump administration has many people cheering this extraordinary intervention. It's nothing to celebrate. Trump himself has tested the American system in ways unseen since the 19th century. It's critical that the pursuit of justice does not merely compound the damage.