Leaders can shape public opinion, perhaps more than they are shaped by it. Public opinion in dealing with terrorism is difficult, however, because it touches upon legitimacy. In the case of Israel-Palestine, both Arafat and Netanyahu must respond to each other's needs without looking like they are caving into each other. The same is true in Ireland.
Governments walk a fine line in shaping public opinion and maintaining legitimacy.
It is interesting that terrorists do not need active public support to operate, just public tolerance or indifference.