To achieve success in the Balkans, President Clinton should beware of Greeks daring rifts. The bitter dispute between Greece and Macedonia over the former Yugoslav republic's choice of a name and a flag is rising to a boil as Clinton prepares for a crucial meeting on the future of the Balkans with Greek Prime Minister Andreas Papandreou.

Forced by intense Greek nationalist sentiment into a more bellicose position than he would have adopted himself, Papandreou is due at the White House on April 22. Papandreou seems confident that America and Western Europe will back NATO ally Greece rather than the fledgling ex-Yugoslav republic.

But that is not the real choice Clinton and the leaders of the European Community face. They need to focus on the growing danger that Greek actions could cause the Balkans war to spread once again -- even as fighting lessens in Bosnia, thanks in large part to Washington's new diplomatic activism there.

While the State Department has reacted with sharp words for the Greeks, the White House has played down American reaction to avoid conflict with the Greek American lobby, as I outlined in this column yesterday.

It is commonplace for American presidents to placate large, powerful domestic lobbies. But the effect in this case is to lend support to Greek policies that are raising tensions and the chance of conflict in the Balkans, where American troops are deployed.

Even as the United States, which has 340 American soldiers in Macedonia, weighs sending more American peace-keepers there, Greek military planning is proceeding for the Greek army to establish a "security zone" 20 or more miles into Macedonia if civil disorder erupts there, intelligence reports show.

Greece's contingency planning, which has been discussed with American military officers who serve on a bilateral military commission, is centered on the possibility that a tidal wave of Kosovo refugees could set off chaos in the region and threaten ethnic Greeks living in Macedonia. Nearly 2 million people, the majority of them Slavic and a sizable minority Albanian, live in the poor, mountainous state.

"The Greeks feel they have consulted us on what they may have to do, and that we have not warned them off," says one U.S. expert aware of the military conversations.

The contingency planning parallels Greek moves that increase the chances for upheaval in Macedonia. The Greeks are pursuing a slow-motion military buildup on their northern frontier. And an economic blockade of Macedonia ordered by Papandreou on Feb. 16 is depleting Macedonia's scarce foreign reserves.

Papandreou's brinkmanship has revived suspicion that Greece and Serbia have already agreed to carve up Macedonia if the conflicts of the other ex-Yugoslav republics spill over there. Both Belgrade and Athens strongly deny these suspicions, initially passed on to Washington by European governments.

The Clinton administration has a direct strategic stake in defusing the crisis. The president ordered U.S. troops into Macedonia last year to deter Serbia from extending its war on Bosnia southward. The Pentagon plans to send another 200 U.S. soldiers to Skopje soon if, as expected, Scandinavian troops now on duty there move across the border to help keep order in Bosnia.

The U.S. presence is intended to shore up the centrist government of President Kiro Gligorov and to bolster the public warnings given by Clinton and earlier by George Bush that the United States would not stand by and watch the Serbs extend violent "ethnic cleansing" into the Albanian-inhabited province of Kosovo.

Those presidential warnings reflect U.S. fears of a nightmare scenario: trouble in Kosovo erupts, triggering massive refugee flows into neighboring Macedonia, which is overwhelmed. Albania, Bulgaria, Greece and/or Turkey could then be tempted to intervene, as might Serbia.

Greece is now a serious candidate for intervention. Athens has refused for two years to recognize Macedonia on the grounds that the country's name amounts to a territorial claim on the Greek northern province of Macedonia. The Greeks demand that Macedonia change its name and its flag, which carries a 16-point star the Greeks claim as an exclusive national symbol, and eliminate phrases in its constitution that promise to defend Macedonians abroad.

Greece has unsuccessfully sought to keep the United States and Western Europe from recognizing Macedonia. Papandreou said he was sending "a signal" to the world with his Feb. 16 decision to close Greece's frontier with landlocked Macedonia and ban its use of the Greek port of Salonika, which normally handles 70 percent of Macedonia's imports and exports. Clinton had recognized Macedonia one week earlier.

Macedonia's agricultural exports and energy imports have ground to a halt. International aid and investment for Macedonia is also hostage to Athens' campaign, which threatens to bring Grigorov down and bring to power the rabid Macedonian nationalist forces Grigorov has sought to contain.

Only Greeks blinded by territorial ambition could want that outcome. Their April 22 White House meeting will be a chance for Clinton to gauge Papandreou's true intentions -- and to make clear that even old allies with powerful friends in America cannot demand U.S. acquiescence for destabilizing and dangerous policies.