By Stephen L. Carter / Bloomberg Opinion

With the trial of Sarah Palin’s defamation suit against the New York Times now in the hands of the jury, her effort to vindicate her reputation looks pretty much done for. The reason isn’t that she lacks a legitimate beef. The problem is that although libel law exists to protect reputation, reputation doesn’t mean what it used to mean.

The case stems from a 2017 Times editorial that inaccurately linked Palin’s political action committee to the 2011 Arizona shooting where six people were killed and Democratic Rep. Gabby Giffords was wounded. At the time of the editorial, the connection had been debunked, including in the pages of the Times. The paper ran a correction within hours.

I have multiple biases here. I was raised by my parents to love the Times, and I still consider it the world’s greatest newspaper. My writing occasionally appears in its pages. But anyone can see that the editorial was a dreadful mistake.

So why does Palin have a problem?

Let’s start with her testimony. She told the jury how “devastating” it was to read “a false accusation that I had anything to do with murder, murdering innocent people.” She described a stress so great that she had trouble sleeping: “It’s hard to lay your head on the pillow and have a restful night when you know that lies are being told about you.” But on cross-examination, Palin was unable to point to evidence of particular harm to her reputation.

This difficulty matters because defamation law only compensates one’s personal pain and suffering in certain narrow circumstances. (At Palin’s trial, the judge essentially instructed the jury not to consider the issue.) Instead, a plaintiff must show that the statement in question harmed her reputation.

That’s a lot harder than it used to be.

Defamation law began in an era when reputation was jealously guarded, especially among the upper classes. Litigation was often the only alternative to pistols at 10 paces, and judges took the task seriously. During the early years of the 19th century, a newspaper could be forced to pay recompense simply for republishing a defamatory allegation made in a civil lawsuit. In an 1814 libel case, a federal court ruled that the fact that a newspaper’s source for the key statement was an open debate on the floor of Congress was no defense. (Although the claim might mitigate damages.)

The era was one in which the printed word was thought to be so influential that the publication of false and defamatory statements was deemed “libel per se,” giving rise to damages without the need to show that the plaintiff had suffered actual harm. The rule was used to protect the reputations of, say, spouses accused of cheating, or adults accused of having been born out of wedlock.

Nowadays these examples might seem quaint, but defamation law has always served a social function, tailoring its details to the perceived mores of the moment. Notoriously, as late as the 1950s, a majority of U.S. jurisdictions held it libel per se to call a white person Black (but not to call a Black person white). And only in 2021 did New York’s highest court reject the traditional rule that falsely calling a person gay was libelous per se.

Today, the social function of libel law isn’t clear. For one thing, since the 1960s, when Southern segregationists weaponized libel law to punish Northern reporters, courts have elevated protecting press freedom above protecting reputation. The best-known requirement is that a public figure who sues must show not negligence but actual malice. That’s a high bar. When the U.S. Court of Appeals for the 2nd Circuit reinstated Palin’s lawsuit last summer, the panel issued a stern warning that a finding of malice requires more than political opposition.

Another change is the decline of libel per se. Apart from few hoary categories — suffering from “loathsome disease,” for example — there isn’t much left that constitutes so great an insult that reputation can’t recover. Consider: In the current moment, few charges are more injurious than being labeled racist. But if you file a lawsuit, most courts will respond that “racist” isn’t defamatory because it merely expresses an opinion.

Most important, our understanding of reputation itself has changed; and not only because reputations can be shredded in an hour. The larger problem is that we’re not much good at separating judgments about a person’s character (probity, integrity, and so forth) from judgments about a person’s politics.

Social scientists have long identified our tendency to believe charges of wrongdoing leveled against members of the other party and reject charges aimed at members of ours. So hardened is the habit that across the spectrum, we have trouble deciding whether an election was fair until we know who won.

All of which is to say that maybe the reason Palin had trouble citing evidence of harm to her reputation was that neither her admirers nor her critics would be swayed by the editorial’s accusations. When reputation rests largely on political positions, it’s less likely to be affected by the kind of charges that once would have constituted libel per se.

I’m not arguing on behalf of Palin, who probably shouldn’t have filed suit once the Times issued its correction. I’m worried about some future plaintiff, with more at stake, for whom today’s highly partisan approach to reputation might prove an unjustly impenetrable wall.

Stephen L. Carter is a Bloomberg Opinion columnist. He is a professor of law at Yale University and was a clerk to U.S. Supreme Court Justice Thurgood Marshall. His novels include “The Emperor of Ocean Park,” and his latest nonfiction book is “Invisible: The Forgotten Story of the Black Woman Lawyer Who Took Down America’s Most Powerful Mobster.”