THE United States must remain implacably in favor of a West Bank peace accord. By sending Middle East specialist Richard W. Murphy to Jordan, Egypt, and Israel, the Reagan administration is commendably keeping its hand in to that end. Immediate circumstances are not encouraging. The current initiative -- the effort of King Hussein of Jordan to engage the United States, and then Israel, in joint talks with a Jordanian-Palestinian delegation -- is getting the long stare and cold shoulder all around. Israel's reservations about building up the Palestine Liberation Organization even indirectly through such meetings are honored in Washington, so the administration has been slow to press for them. Ironically, even the prospect that moderat e Arabs may succeed in initiating a peace process arouses a nervousness on whether anything might come of it. In the background is the possibility that a Camp David formula, with moderate Arabs and Israel brought together under US mediation, rather than an international conference format, would present Israel with an opportunity it could not refuse. Hence the pressure on the Reagan administration in Tel Aviv, and in Washington by Israel's supporters, to contain the Murphy mission. Israel's foreign minister,
Yitzhak Shamir, called the mission ``dangerous.'' To counter this resistance, the State Department felt compelled to state: ``We will not participate in indirect negotiations or pre-negotiations.''
In Casablanca, Hussein's Arab world allies declined to endorse his initiative, launched Feb. 11 in Amman with PLO leader Yasser Arafat. They did not, however, reject it outright. Syria and Libya would not even attend the Moroccan summit; Syria, of course, remains set against any peace plan to which it is not a party -- if, indeed, it does not prefer to keep Jordan and Israel discomfited into the foreseeable future.