IT is shameful that the government of the United States has been unable to say more about the assassination of Sheikh Yassin than that it was deeply troubled by it especially since it took the better part of ten hours to come up even with that evasive formula. Does President Bush condemn the assassination or not? His administration has previously said that it is opposed to targetted killings by Israel. Why has it not been able to say as much in this case? That the need for Mr Bush to clarify his position is urgent was underlined by yesterday's statement by Israel's Public Security Minister that Everyone in Hamas is in our sights. How many more killings will be necessary before Mr Bush finds it possible to define his position? It is being suggested that the President is inhibited from sending an unambiguous message to Mr Sharon by three factors: first, that Israel insists on portraying Hamas as the kind of organisation that America's war on terror is aimed at; second, that Israel's projected plans to withdraw from Gaza and the West Bank should be allowed to go ahead without interference from other considerations; third, that condemnation of Israel's actions at this juncture would alienate the influential Israeli lobby and Jewish voters in the United States ahead of the November Presidential election. Whatever the strength of these factors - and the last-mentioned is certain to be at the forefront of Mr Bush's mind - the more important consideration is that Sheikh Yassin's death and others that may follow it will further destabilise the whole of the Middle East, rendering the rehabilitation of Iraq even more difficult and the prospect of wider moves towards stability in the region even more distant.