“When we issue an opinion, we are aware that every word that we write can have consequences, sometimes enormous consequences,” Justice Samuel A. Alito Jr. said last month. “So we have to be careful about every single thing that we say.”

A fascinating new study of the extraordinary impact of a tiny typographical error in a Supreme Court opinion almost a century ago illustrates the point.

The mistake appeared in a slip opinion issued in 1928, soon after the court announced a decision in a zoning dispute. It contained what seemed like a sweeping statement about the constitutional stature of property rights: “The right of the trustee to devote its land to any legitimate use is property within the protection of the Constitution.”

But the author of the opinion, Justice Pierce Butler, had not meant to write “property.” He meant to say “properly.”

Slip opinions are preliminary and subject to editing. They are eventually supplanted by the authoritative versions in hardcover books.

The court eventually fixed the mistake, and this is what appears in the final version of the opinion published in book form in United States Reports: “The right of the trustee to devote its land to any legitimate use is properly within the protection of the Constitution.”

Though the opinion was amended, the court did not draw attention to the change and the correction went unnoticed in much of the legal world.

The wrong version of the statement has appeared in at least 14 court decisions, the most recent of which was issued last year; in at least 11 appellate briefs; in a Supreme Court argument; and in books and articles.

Michael Allan Wolf, a law professor at the University of Florida who discovered the mistake and traced its history in the new article, to be published in The Washington University Law Review, said it was the worst sort of typographical error.

“It is a real word,” Professor Wolf said in an interview. “It makes sense in context. And it changes the meaning.”

He said it was impossible to know whether the incorrect statement affected the outcome in the cases in which judges considered or cited it.

“We’ll never know the answer to that,” he said, “though if we have judges who favor the private property owner at the expense of the government, I think it could be more than just icing on the cake.”

In all, though, Professor Wolf said, the oft-cited mistake served to amplify one view of property rights.