WARREN CHRISTOPHER, the US Secretary of State, has begun a trip to the Middle East and Europe on which he is expected to try to push forward stalled talks between Syria and Israel, writes Charles Richards. The first stop is Israel. He is then to go to Damascus, Cairo, Amman, Tunis and Rabat. He is also to meet the PLO chairman, Yasser Arafat. US officials say Mr Christopher will be looking for an exchange of letters between Syria and Israel. Syria says it will exchange total peace for Israeli withdrawal from the Golan. Israel says it will withdraw on the Golan, not from it, but wants to know what Syria envisages by total peace.