The Union vs. Dr. Mudd

[RJNorton]

The case is discussed here.

For what it's worth, Wikipedia says the Supreme Court ruled in this case that:

(1) A pardoned man must introduce the pardon into court proceedings, otherwise the pardon must be disregarded by the court.

(2) To do this, the pardoned man must accept the pardon. If a pardon is rejected, it cannot be forced upon its subject.

(3) A pardon carries an 'imputation of guilt', and accepting a pardon is 'an admission of guilt'.