THE FAILURE TO REACH even a brief humanitarian lull in the fighting illustrates the difficulties in securing a more permanent truce as the sides remain far apart on their terms.Netanyahu vows Israel will do 'whatever is necessary' in fight with HamasObama tells Netanyahu US worried about mounting deathsEXCLUSIVE: UN studies formal Palestinian plea for a protectorateVIDEO: What are the keys to a lasting cease-fire?