Sadly, this has been a week when local jealousies and narrow self-interests delayed and perhaps even spoiled two worthy projects that could have brought new stability to two important parts of the world.
The feuding clansmen of Lebanon found themselves incapable of reconciling their differences - even when they met within the tranquility of Switzerland and being prodded by the Syrians, who arm most of them, and the Saudis who subsidize all. Their only agreement was to try to improve the cease-fire back home and authorize a commission to study further the problem of a new constitution for their torn and bleeding country.
The nationalists of Western Europe found themselves equally unable to reconcile their money problems even when the bureaucrats of their Common Market organization in Brussels had partially resolved the awesome problem of their milk surpluses. Still unresolved was the bitter and divisive dispute over reducing the British contribution to their communal funds.
Neither failure was necessarily fatal.
Conceivably the Lebanese will, with more time (and more damage to life and property from continued clan fighting), work out a compromise. And the Common Market leaders will be meeting again in June.
In both cases, it was of minor interest that the United States was a bystander, watching with hope for a successful resolution but with no cards to play in either affair. The time when the US could arrange such things is well in the past in this more pluralized world of today.
President Reagan's main active foreign policy project continues to be the ''saving'' of El Salvador. He and his lieutenants were busy this past week urging Congress to provide more funds both for the official government in El Salvador and for the insurgents in Nicaragua whose activities are supposed to reduce the amount of aid Nicaragua can give to the insurgents in El Salvador.
This week saw a new dimension added to the guerrilla war against the Nicaraguan government: a mine, presumably obtained originally from the US, went off in Nicaraguan waters, damaging a Soviet tanker carrying fuel to Nicaragua. The Nicaraguans claimed that the US is making war on Nicaragua. It is, but through proxies; and, in theory, the war is still ''covert.''
The pity about both the two top diplomatic failures of the week was that in both cases success seemed almost at hand and could have revived positive momentum.
In the hotel at Lausanne, where the clansmen of Lebanon met, the Syrians had a compromise package ready. But at the last moment the plan was rejected by a member of one of the three main Christian Maronite families - Suleiman Franjieh. Perhaps partly it was the result of old hostilities between Franjiehs and Gemayels. Whatever the reason, the older leaders of the Maronite families - the Chamouns are a third - are not yet willing to give up the control they have traditionally held on the economy of Lebanon.
The failure at Brussels was more serious. It does not end the Common Market. But it does expose the fact that the historic post World War II effort to move the West European countries more closely together is not just faltering but possibly reversing.
Getting Britain fully into the Community was never going to be easy. This past week that problem was still at the center of the difficulties. In effect, the British complain that they are being required to subsidize uneconomic high production of food in West Europe, especially in France. The British are tired of carrying what they think is an excessive share of the cost.
The form of a united Europe, and the formal organization, will undoubtedly continue for a long time. And the negative drift of today may be reversed by some event in the future. But right now individual nationalisms seem to be more vital in the community than the collective gains of Europeanism.