John Campbell on Legal Infallibility

According John W. Campbell:

A simple, clear, and yet rather subtle example of that doctrine of Legal Infallibility is the fact that if a man is tried and convicted of a crime, and it is later discovered that it was a case of mistaken identity—the wrong man was convicted—the Governor of the State signs a pardon!

How can you pardon a man for something he didn't do?

It's the only thing you can do under the hidden-postulate rule that the Law is Infallible. You can't sign a Certificate of Exoneration; that would mean that the Law had been wrong!

This sounds relevant to current events somehow…