AP Photo

On Monday, a secret Hezbollah munitions bunker in South Lebanon blew up under mysterious circumstances, injuring a senior official in the organization. This is the second such incident in recent months. The first occurred on July 14, when an explosion destroyed a major Hezbollah munitions dump in the South Lebanese village of Hirbet Salim. Hezbollah immediately pointed fingers at the Mossad. Whether or not Israel was to blame, the explosion caused Hezbollah considerable discomfort by proving that it was in flagrant violation of U.N. Security Council Resolution 1701, which forbids stockpiling weapons south of the Litani River.

The U.N. issued a strongly worded rebuke and sent representatives to investigate. But their efforts were thwarted by Hezbollah fighters, who, with the...