WHILE the West was captivated by the Soviet coup, the Serbian-led Yugoslav Army devoured a third of Croatia, and that is just breakfast in the Serbian scheme of things. A full half of the country is about to be occupied. Villages are being destroyed. Between 500,000 and 700,000 Croats face either refugee status, with the loss of homes, businesses, and land, or life as a hated minority under a military dictator. Ominously, a Serb general told a US diplomat in Europe last week of a campaign to force Croatsout of the Army-held part of Croatia. He compared this to the Poles' forced repatriation of Polish Germans after World War II. Peace talks sponsored by the European Community remain the best hope of ending the conflict. But if they fail, the West must decide how to deal with Serbia. It's a strange echo after the Persian Gulf war, but will this aggression stand? Is this simply an internal matter? Should Western nations come to Croatia's aid by sending in peacekeeping troops? The Croats are not guiltless. They provoked the Serbs in countless subtle and overt ways over the past year. They wrote a new constitution, giving no special rights to Croatia's Serbs, an already paranoid minority butchered by the tens of thousands by Croats during World War II. They waved the Croat checkered flag - something akin to waving a Confederate flag at an NAACP meeting. They forced Serbs to take loyalty oaths and recently fired many of them from government jobs. Yet none of these acts can excuse the brutal aggression of Serbian President Slobodan Milosevic. The Croats may have courted the war they are getting, but they do not deserve it - or the new border Milosevic is drawing through Croatia. The West faces a dilemma. The EC is not set up to supply arms. It would not be politic for the US to do so. But past policies supported by the West are now hurting Croatia. A year ago the Croat militia was asked by the federal Army to give up its weapons. Croats did so, whereas their Slovene neighbors did not. Both the US and the EC counseled the Croats not to take up arms and to accept the arms embargo they then placed on Yugoslavia. The Croats did so. At some point, a line must be drawn. The West may feel unable to send weapons at this juncture or help Croatia recover lost land. But if federal Army forces push farther into Croatia, the West must find a mechanism to help the Croats defend themselves against a bloodbath. There are recent precedents, including a UN mandate against internal genocide applied both to Ethiopia and to Iraq during the Kurdish crisis.