WHILE Israel's Prime Minister Ariel Sharon was trying, but failing, to persuade Tony Blair that Yassir Arafat is an obstacle to progress on the Israeli/Palestinian road map and should therefore be arrested or deported, events in Palestine itself showed the wisdom of the British position. Mr Arafat and his prime minister, Mahmoud Abbas, announced that they had worked out a power-sharing agreement that should ease the difficult relationship between these two long-term colleagues in the Palestine Liberation Organisation. The agreement returns to Mr Arafat some of the power he appeared to have lost since the United States and Israel picked out Mr Abbas as the man with whom they wanted to do business. Although this support appeared at first to put Mr Abbas in a strong position it also made him vulnerable to the accusation that he was an Israeli/US puppet, especially when his initial negotiations with Mr Sharon did not extract as many concessions as Palestinians had expected. Under the new agreement, three committees with representation from both Mr Arafat's and Mr Abbas's supporters will oversee the broad lines of the negotiations on the road map provisions to be followed by the prime minister. There is not much doubt that this represents a reining-in of a prime minister who was beginning to take positions that did not accord with mainline Palestinian thinking. Washington and Jerusalem will not like this development but it should serve as a warning to them of the danger of pushing negotiations too far and too quickly past the point that is acceptable to the broad base of indigenous opinion.