ISRAEL last night threatened to assassinate Palestinian Prime Minister Ismael Haniyeh if Hamas militants did not release a captured Israeli soldier unharmed. The unprecedented warning was delivered to Palestinian President Mahmoud Abbas in a letter as Israel debated a deal offered by Hamas to free Corporal Gilad Shalit. It came as Israeli military officials readied a second invasion force for a huge offensive into Gaza. Hamas's Gaza-based political leaders, including Mr Haniyeh, had already gone into hiding. But last night's direct threat to kill Mr Haniyeh, a democratically elected head of state, sharply raised the stakes. The bid to free...