Hamas and the Islamic Jihad say Israeli military actions could prompt them to quit the cease-fire. “If Israel continues its aggression, we will have to respond,” said Mohammed Al Hindi, the leader of the Islamic Jihad in Gaza. The threat underscores the fragility of the truce. Palestinian leader Mahmoud Abbas is not strong enough to enforce it and depends on the goodwill of the terrorists. As a result, Israel says terror groups hold a veto over the peace process.