The US Supreme Court has long made a habit of post-opinion editing:
The Supreme Court has been quietly revising its decisions years after they were issued, altering the law of the land without public notice. The revisions include “truly substantive changes in factual statements and legal reasoning,” said Richard J. Lazarus, a law professor at Harvard and the author of a new study examining the phenomenon.My police friends told me long ago that there is no such thing as a "law-abiding citizen", that the traffic laws were explicitly written to permit them to exercise their judgment and pull over anyone, at any time. But it's interesting to see that virtually no one has even a theoretical chance of knowing what the law is, given the way that interpretive case law not only trumps black-letter written law, but is susceptible to behind-the-scenes editing at any time.
The court can act quickly, as when Justice Antonin Scalia last month corrected an embarrassing error in a dissent in a case involving the Environmental Protection Agency.
But most changes are neither prompt nor publicized, and the court’s secretive editing process has led judges and law professors astray, causing them to rely on passages that were later scrubbed from the official record. The widening public access to online versions of the court’s decisions, some of which do not reflect the final wording, has made the longstanding problem more pronounced.
Unannounced changes have not reversed decisions outright, but they have withdrawn conclusions on significant points of law. They have also retreated from descriptions of common ground with other justices, as Justice Sandra Day O’Connor did in a major gay rights case....
After-the-fact editing is not a new phenomenon. “The current court did not begin this practice, which finds its origins in the court’s earliest days and has extended to all justices over the years, liberal and conservative, but the court today can take the steps to correct it,” Professor Lazarus said. “Easy to do, and long overdue.”
The court seems to have been even more freewheeling in the past. Chief Justice Roger B. Taney added approximately 18 pages to his 1857 majority opinion in the Dred Scott decision after it was announced.