Why did the Speaker of the House go before the press to declare that the charges against the president are “an impeachment that will last forever”? Mrs. Pelosi used the phrase just before sending the charges over to the Senate. She was flanked by the two key managers who will prosecute the case, Congressmen Jerrold Nadler and Adam Schiff, who showed no emotion. Yet the more we rolled her phrasing over in our mind, the more it struck us as peculiar — off — and even an abuse.

For, at least to us, Mrs. Pelosi spoke as if she doubts her impeachment managers can win a conviction. What she was saying was that she comprehends she is likely to lose but is proceeding anyhow for the purpose of marking the President’s reputation and tarnishing his legacy (and damaging his election chances 10 months hence). She mightn’t gain a conviction, she seemed to be saying, but it is enough to make the charge. The charges themselves will last forever.

Even, the Speaker was suggesting, if there is an acquittal. And that is something to think about. It sent us back to our dog-eared copy of Robert Jackson’s famous speech called “The Federal Prosecutor.” The future Supreme Court justice was attorney general when he delivered his remarks to a gathering of United States attorneys. His aim was to mark for them the need for humility, objectivity, fairness, and decency. And warn of the lurking temptation to abuse of power.

A prosecutor, Jackson asserted, “stands a fair chance of finding at least a technical violation of some act on the part of almost anyone.” That phenomenon, he seemed to suggest, hisses an invitation to hubris. In such a case, “it is not a question of discovering the commission of a crime and then looking for the man who has committed it, it is a question of picking the man and then searching the law books, or putting investigators to work, to pin some offense on him.”

Then the famous words: “It is in this realm — in which the prosecutor picks some person whom he dislikes or desires to embarrass, or selects some group of unpopular persons and then looks for an offense — that the greatest danger of abuse of prosecuting power lies. It is here that law enforcement becomes personal, and the real crime becomes that of being unpopular with the predominant or governing group, being attached to the wrong political views, or being personally obnoxious …”

We understand that an impeachment is not the same as a criminal proceeding in a conventional court. Yet Jackson put his finger on the very character flaw that Mrs. Pelosi and Messrs. Nadler and Schiff seem to have brought to this drama. It becomes an abuse when one proceeds in the face of the likelihood of acquittal. Acquittal is not certain — these columns have been warning about that — but acquittal is likely, and Mrs. Pelosi and the accusing Democrats know that.

Hence her remark about this being an impeachment that will stand forever. Justice Jackson is long gone, sadly, but we found ourselves thinking all evening about what he might have said had he seen this day. He himself was a Democrat down to the ground. He warned, though, against partisanship in prosecutors. He’d have, we suspect, been horrified at a House seeking satisfaction in the idea that it will be the accusation that will stand throughout history — rather than the verdict.