THE strife between the Yugoslav Army and Slovenia flared again Tuesday as European diplomats stepped up efforts to make a cease-fire work. The crisis - with its clash of nationalistic aspirations - is a major test of Europe's post-cold-war peacemaking ability.By putting up a stubborn defense, the Slovenes have essentially thrown themselves on the West's mercy. Concern over destabilized borders, less than support for an emerging democracy, brought the European Community into the Balkan peace business. The West has been a bit reluctant to put itself in the middle of a problem it foresaw if Slovenia persisted in seeking independence. But it had little choice. Resolution of the Balkan conflict hinges on the Slovenes' being more conciliatory than they have been. That will not be easy, since they have just experienced a heady surge of national feeling as a result of declaring independence and then being attacked for it. But the Slovenes, too, have little choice. One main reason is the mentality of the Serbian-led military. By waving their independence in the face of the Army and now insisting that federal troops in their republic be disarmed, the Slovenes have humiliated Yugoslavia's generals. Many of these military men give enormous weight to a traditional Balkan sense of honor. In many cases, they would rather fight and be defeated than not fight. Serbian generals in the conflict with Slovenia have felt mocked by the better-off northern Yugoslavs, whom they are likely to regard as "cowards." Deep resentments are coming into play. But, sensitive to world opinion, the generals have not brought their full firepower to bear on the Slovenes. If the Slovenes are as serious about independence as they have shown so far, they will understand the need to help the military save face through the process of cease-fire and negotiation. Nothing is going to take away the pride the Slovenes now feel. They proclaim Slovenia's right to be independent. This claim can't simply be dismissed. US and European policy regarding Slovenia needs to be reviewed. Why should it be constrained to live under the threat of force? But Slovenia is also responsible for its actions and their effects - which could lead to a larger war in Yugoslavia. What about the impact on Croatia or on civil life in Bosnia? For Slovenes simply to say or imply "That's not our business" doesn't live up to the ideals they profess to hold.