For example, the fact (if it is a fact) that Ned Lamont is a bad singer is irrelevant to whether or not one should vote for him.
But what about the following video?
Are there claims made in this ad hominem attack on Harold Ford that, if they were true, would be relevant to whether or not one should vote for him? If so, what are those claims? Do they constitute a legitimate--as opposed to fallacious--ad hominem argument?