The Genocide Convention (1951) focuses on large-scale population killing, but no international convention yet deals specifically with lesser-scale massacres.
The events that could trigger widespread violence are usually different from the events that trigger a preventive response from outside parties. It would not, for example, have been possible to give an unambiguous, precise warning that a plane crash in Central Africa would precipitate the slaughter of nearly one million people. But many earlier indications of the possibility of genocide in Rwanda in 1994 were ignored, and no preventive plan of action was in place.
Specialists may disagree on the scope of preventive diplomacy and, more broadly, preventive measures of various kinds. They may differ also in their assessment of policies and strategies to ward off undesirable events. There is no disagreement, however, on the importance of obtaining early warning of incipient or slowly developing crises if preventive action is to have any chance of success.