[Infidel753 commented on my post, A Conservative's [sic] Moral Vision. I believe his remarks deserve more prominence; with his permission I have reproduced the comment here, removing only content that refers to other posters' comments. His original text can be found in the comments section of the linked post.]
I'll respond to what you call your "quibbles" with one of my own: I don't self-identify as a "conservative". I'm pretty much used to liberals calling me a conservative and vice-versa, though.
To me, the imperative to prevent the destruction of Israel springs from the same broad principle as my having engaged in abortion-clinic defense -- the broad principle of defense of freedom.
I think one difference between your approach to "moral principles" and mine is that you apply them mostly to tactics and I apply them mostly to outcomes. You use your principles to classify particular tactics as allowable or non-allowable, and renounce the ones you consider non-allowable even if this results in an outcome which, overall, is worse than could be produced by utilizing those tactics. I use my principles to determine which outcome is most desirable (or, as in this case, least undesirable) and judge tactics by their likelihood of achieving that outcome.
Most of the counter-arguments take the form of:
(1) stating a historical or hypothetical situation which is claimed to be analogous to the Iran/nuclear issue;
(2) describing a possible action which is claimed to be analogous to my own proposed action in the Iranian case (an airstrike) but which the reader is expected to judge to be self-evidently inappropriate or immoral;
(3) claiming that the airstrike is thus also inappropriate or immoral.
For me this kind of argument doesn't work. No two such situations are ever similar enough for the "wrongness" of a given action in one case to demonstrate the wrongness of a supposedly analogous action in another case. With hypotheticals, such as a Pakistani threat against India, there are so many factors to take into account that it's impossible to say what I would consider an appropriate response without having an actual case to look at.
What the same arguments might or might not justify another country doing in an analogous position isn't the question I'm addressing. We are who we are, Americans, in a particular time and situation; the question is what action (or inaction) on our part gives the best or least-bad result in the situation we are actually in.
I think it is worth pointing out that we have obligations toward our friends and allies and their interests which we do not have toward our enemies. Israel is our friend and ally, Iran is not. I consider it perfectly legitimate to favor the interests of the United States and of Western civilization simply because they are the country and the civilization I come from. This doesn't require me to believe that the US or the West are morally or otherwise superior to their rivals (though in fact I believe they are).
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Finally, I am not really trying to persuade anyone whose mind is already made up; that's pretty much impossible. You and I are not going to convince each other. The proper role of argumentation of this kind is to persuade those who are yet undecided. With that in mind, I can only invite interested readers to look at the original posting and see for themselves whether they think it makes a coherent case or not.