W. Averell Harriman, President Truman’s special envoy, is engaged in one of the most important missions of his career—the effort to resolve the bitter oil dispute between Iran and Britain.

Mr. Harriman left Washington with President Truman’s assurance that the sole American interest in this issue is “world peace and the welfare of Iran.” With him also was Iranian Premier Mossadegh’s assurance of welcome in his mediation effort.

But welcome is not synonymous with co-operation. So far the Iranian government has displayed no tendency whatever to compromise its policy of taking over the Anglo-Iranian Oil Co. lock, stock and barrel.

And Britain, while expressing formal pleasure at the prospect of having Mr. Harriman consult with her ambassador to Iran, Sir Francis Shepherd, has indicated no commitment to accept Mr. Harriman as mediator.

But Mr. Harriman is confident the dispute can be ironed out satisfactorily to both sides. Surely Mr. Harriman would not have been sent to Iran if his mission was hopeless. The free world will watch his endeavors with deep interest and sincere hope for their success.