The worst form of impeachment verdict was: 'He did it, but it wasn't that bad'

"Hypocrisy is the tribute that vice pays to virtue."

The public Senate deliberations in President Donald Trump's impeachment trial reminded me of this famous maxim, coined in the 17th century by the French aristocrat and aphorist Francois de la Rochefoucauld.

From a constitutional standpoint, it would be better if Trump was acquitted because his defenders find the evidence unconvincing — even if they are being hypocritical — than for them to say that Trump's alleged conduct was fine.

That's because the precedent set by Trump's trial depends heavily on the senators' explanations for their votes. If future observers see that the senators redefined impeachment so that it did not include the president abusing his power to cheat in an election and obstruct Congress, that will profoundly weaken the U.S. constitutional system. It will weaken the political virtue of the republic.

But by saying that they simply don't believe the charges, senators supporting acquittal can pay some tribute to the Constitution and its protection of political virtue. They would recognize that abuse of power and obstruction of Congress are impeachable acts.

This hypocrisy would leave the country better off than an honest statement by these senators that they just don't care what Trump did.

It's important to understand why the Republican senators' explanations matter so much to the long-term meaning of this whole impeachment undertaking.

The historical record will include four major components: the witnesses' testimony before the House; the articles of impeachment themselves, which reflect the beliefs of the House's Democratic majority; the legal arguments made before the Senate, both by the House managers and by Trump's lawyers; and the explanations of the Senators who voted on the winning side.

The facts established by the testimony are convincing. My guess is that in the long term, no one will really doubt that Trump froze military aid to Ukraine as part of his plan to pressure the new Ukrainian president to announce investigations into Joe and Hunter Biden and into the CrowdStrike conspiracy theory.

The House's view of these events, as recorded in the articles of impeachment, only matters as a kind of indictment: It's the perspective taken by the prosecutor. Prosecutors' views do not necessarily establish precedent. Ordinarily, precedent in a trial comes from the reasoning expressed in the outcome.

Arguments by the managers and Trump's lawyers will carry more weight in giving meaning to the outcome of the trial. That's to be expected, especially when the verdict is rendered by a jury that is not under an obligation to give a reasoned explanation for its decision. Yet future observers will likely apply a discount factor to the legal arguments made on both sides.

That means that the most important component of future attempts to assign meaning to the outcome of the Trump trial will be the explanations the senators provide about their votes. In Bill Clinton's impeachment trial, the Senate held its deliberations entirely in secret. That made it a lot harder to assign a concrete meaning to the Senate's vote not to remove him from office. In contrast, the public speeches by the senators this time around will create a permanent public record.

The worst possible outcome is for senators to say there's nothing wrong with what Trump did, and that the public should just get over it. This is the kind of dangerous honesty that La Rochefoucauld's maxim points out: Vice's brazen ignoring of virtue. That tends to destroy virtue itself.

Noah Feldman is a professor of law at Harvard University and was a clerk to U.S. Supreme Court Justice David Souter. His books include "The Three Lives of James Madison: Genius, Partisan, President."