The Archbishop of Canterbury calls to mankind far beyond his world-wide Anglican community when he seeks a moral way out of the Falklands crisis. ''The purpose of using force is to achieve a just political settlement, not a military victory,'' wrote Archbishop Runcie in the Times of London on the weekend. His words came just as both sides were displaying fresh interest in United Nations mediation efforts by Secretary General Perez de Cuellar.
The archbishop noted that Britain had had a moral duty to stand up to Argentine aggression in taking over the Falklands. Recent British polls and local elections suggest widespread support for the Conservative government's tough response. But argument remains in Britain and abroad over whether there was a British military overreaction. One question is whether the Argentine aggression could not have been stood up to with no less long-term effectiveness if UN mediation had been turned to in the first place.
At any rate, force was met with force, bringing what Archbishop Runcie called ''sickening losses on both sides.'' He pleaded that the cost of every action be counted. He warned: ''It is possible for a war to be waged at such a high cost and to entail so much suffering that this would outweigh any attainable good.''
Perhaps such a realization was already sinking in on some Britons and Argentines. Negotiators on both sides were said to be approaching partial agreement on Mr. Perez de Cuellar's plan for a cease-fire followed by phased withdrawal of Argentine troops and British ships. There remained a problem in how the Falklands should be administered during negotiations for a final settlement, including the matter of sovereignty. A disappointing aspect was the reported belittling of the UN effort by Washington after its failure in shuttle diplomacy. The hope was that agreement could continue to be pursued diplomatically without undercutting by military events.
Here is where the words of Archbishop Runcie might be kept in mind. He is not unfamiliar with war. He received the Military Cross for his service in World War II. He is not unfamiliar with world affairs. He has traveled widely. As Archbishop of Canterbury he has a seat in Parliament and is a member of the House of Lords. What he says now is not unexpected from the man who addressed the Los Angeles World Affairs Council on ''Morality and World Affairs'' just a year ago:
''I believe that we must start to view the world from the understanding that all men and women are brothers and sisters. That is for me not rhetoric but sober fact. God is our father, the father of the whole world. We are world citizens. No great religion, least of all Christianity, suggests that moral obligations begin and end with the citizens of one particular national state only.''
The Falklands crisis has threatened to be a throwback to days when these brothers and sisters futilely sought to solve conflicts through war. Instead, under the archbishop's view, which is shared by so many, it could become an example of pulling away from more bloodshed and proving that men and women have advanced in understanding the sober fact of their common humanity.