a pardon for latimer is tricky, as there are certain aspects of the case that indicate foresight. the problem here is clear intent, and the law doesn't tend to forgive that when the consequences are so severe. the pardoner may be less interested in these details.
but, for these reasons, a retrial is not worthwhile; whatever the merits (or lack thereof) of his actions, he admitted to a first degree murder, and there just isn't room for free speech, there.
i'd like to see arguments. it's one of those things where the reasons are more important than the outcome.