In her highly interesting How Terrorism is Wrong (which I've commented on previously here), Virginia Held states:
"If, however, an existing political system refuses to allow the expression of moral arguments designed to transform it and if an act of political violence can constitute such an expression, it may be morally justifiable" (Oxford University Press, 2008, p. 138).
Held is clearly not stating that all acts of political violence are morally justifiable (a) if they could constitute an expression of a certain kind that is (b) denied by a political system. However, there seem to be at least two important (and missing) qualifications.
The first is that the persons desiring hitherto denied expression of certain moral arguments should be members (whether as citizens or residents) of the political system in question. This is not to say that non-members from other political systems are unable to pass justified comment on rival systems, but I don't think system x has any right to violence against system y on the sole grounds that the latter system doesn't want to hear what the other system wants to say. It seems to me that other conditions must hold, such as the fact that system y is harming its people, for example.
The second missing qualification is all things considered, as in the expression of moral arguments all things considered. It is far from inconceivable to imagine a group whose only desire is to see the world burn. What would constitute "sufficient expression" without which they might attack the rest of us? Would this be a blog, a newsletter or the opportunity to create a viable alternative political party? Or say a group wanted to "express" moral arguments, but the expression was pure hate language or defamatory: again, what would constitute "sufficient expression" without why they might attack the rest of us?
More importantly, are there some forms of expression that should be prohibited? If so, then it strikes me that the view above is problematic. Am I alone?