Moral courage is the form of courage exhibited by someone who acts well, in the face of danger, in the service of one's convictions--the "courage of conviction." We can distinguish moral courage from the merely physical courage of someone who enters into dangerous action (while aware of the risks and perhaps fearful, but not uncontrollably so, of them) in that the morally courageous person acts in defense or pursuit of something of central value to him or herself. (At the same time, moral courage may often involve significant physical courage.)
It is easy to praise moral courage (and courage in general) when its manifestations square with our own expectations and values. Thus, Socrates, Gandhi, and Martin Luther King, Jr., are for us obvious exemplars of moral courage. But then we turn to cases like the 9/11 hijackers, suicide bombers, Scott Roeder (the man who murdered Dr. George Tiller, an abortion provider), and other "fanatics," and it becomes clear that if these individuals are also morally courageous--they seem to have had the "courage of conviction"--then moral courage can motivate behavior that we feel ought to be condemned.
In a previous post I raised some questions about whether "sneaking around" or otherwise attacking one's foes at moments of ordinary human vulnerability can be reasonably described as courageous. I want now to frame this more specifically in terms of moral courage. If Socrates, Gandhi, and King are to be taken as paradigms of moral courage, then I would suggest that an important feature of their actions has to do with the manner in which they each faced their adversaries. Namely, they faced them as one subject to another subject. They did not objectify, or otherwise circumvent a direct confrontation with the will of the other. This was not a matter of giving their adversaries a "fighting chance," but rather a matter of acknowledging the subjectivity of those who would oppose their values and convictions. The following is part of what I say about this in an essay I'm working on:
When one acts for the sake of a cause, one expresses value to others; one’s actions are addressed to others as an expression of that value. But if one objectifies the other, then one treats that other as something unable to receive that expression of value. Objectification precludes the possibility of facing the other, because objects do not have a face (in this sense). The person who refuses to acknowledge the reality and subjectivity of the other, and refuses out of fear, or who circumvents an open confrontation with those others, as subjects, is thus a kind of coward.
If this is right, then it indicates why "fanatics" who treat their foes as dispensable (as mere means) cannot be regarded as morally courageous. Such individuals incur danger in the service of their causes, but they fail to "act well" in the service of those causes because they act against their foes in ways which seem, to me at least, to be incompatible with an honest facing up to those others whom they harm and often destroy. Thus, as above, in one sense, their actions may involve cowardice. In another sense, their actions are reckless.