Consider these two cases:
- Martha hears Patrick utter an insult against her husband. Incensed by the insult, she fights Patrick with her fists, trying to kill him in a "fair" way (Patrick is not weaker than she is, she is not sneaking up on him, etc.). She succeeds in winning the fight, and has, thus, deliberately killed Patrick.
- Constantine tortures a small reptile, knowing the reptile to be entirely harmless.
What Martha has done is, intuitively, morally worse than what Constantine did. Martha killed a person, a creature in the image and likeness of God, a being endowed with dignity. She was provoked, but nonetheless acted deliberately to cause the death of a juridically innocent human being. On the other hand, Constantine caused wanton and inexcusable pain, but he did this to a being quite low down on the scale of moral concern. (If you disagree with my comparison between the two actions, then change the reptile into a ladybug.)
However, Constantine's action is the one that is more expressive of a vicious character: a character that is cruel, cowardly and irrational. Martha's action, while admittedly exhibiting disproportionate wrath, also exhibited loyalty and courage, albeit of a misguided sort. We wouldn't want to have Constantine among our friends. On the other hand, having Martha as one's friend would be an asset, as long as we were careful in our behavior around her.
If this is right, then there is a distinction between how wrong an action is and how expressive it is of a vicious character. This distinction has some interesting consequences. An obvious one is that it makes implausible Hume's account of punishment. Hume thought we punished actions insofar as they were evidence of a vicious character. But we would rightly punish Martha more severely than we would Constantine.
But a more important consequence is that it puts into question the virtue ethics project of grounding moral permissibility and impermissibility in virtue and vice. For, surely, if impermissibility is to be grounded in virtue and vice, then an action is more impermissible—more wrong—if it is more expressive of vice. But the above examples show that this is not so.