By William Drozdiak
Washington Post Foreign Service
Wednesday, March 24, 1999; Page A23

The NATO decision to attack a sovereign nation for the first time in its 50-year history represents a dramatic transformation for an alliance conceived to protect Western Europe from a Soviet-led invasion. Should airstrikes against Yugoslavia actually be carried out, they would serve as a pivotal test for the Western alliance at a time when it is debating its future strategic concept in advance of next month's leadership summit in Washington.

The United States wants NATO to assume a broader mandate by combating such global threats as terrorism and the production of weapons of mass destruction outside the territory of its 19 members. But European countries argue that NATO must concentrate its resources on containing ethnic rivalries closer to home and other immediate challenges to European stability.

With NATO poised to wage war in the Balkans, the European perception may acquire greater importance for the summit, at which government leaders will approve a new mission statement for the alliance.

A key aspect of NATO's evolving role, however, remains unresolved. During the Cold War, it confined military planning to protecting its own territory. But as it confronts security threats outside its countries' borders, it will often find itself at odds with the United Nations and other international organizations.

NATO diplomats say there is a risk that airstrikes may backfire by spurring Yugoslavia to broaden the Kosovo conflict, either by firing artillery at NATO peacekeepers in nearby Bosnia or by escalating an ethnic cleansing campaign in which the forced exodus of Kosovo Albanians could disrupt neighboring Albania and Macedonia.

Even if those fears are not realized, the planned NATO air campaign would set an important precedent that some experts say could come back to haunt the United States and its European allies.

By launching air attacks beyond their own territory against a sovereign country and without a clear U.N. mandate, the 19 NATO states can be accused of flouting the rules of international law and providing justification for other countries to ignore the will of the U.N. Security Council.

The United States encountered resistance on the airstrikes from European countries that insisted the alliance needs explicit U.N. authority before it could attack a sovereign nation. The United States argued that this requirement would enable Russia and China -- two of the five permanent Security Council members -- to exercise a permanent veto over NATO military operations.

When NATO bombed Bosnian Serb military targets in 1995, it was not attacking a sovereign country -- and it had a U.N. mandate for that operation.

The concern over lack of a clear U.N. mandate -- shared to varying degrees by Britain, France, Italy and Germany -- was overcome only when the allies became alarmed by the growing number of ethnic Albanians made homeless in recent weeks as Yugoslav and Serbian forces pressed their offensive against separatist rebels in Kosovo, a province of Serbia, Yugoslavia's dominant republic.

Over the past two days, allied leaders gave formal approval to military action during telephone consultations with NATO Secretary General Javier Solana. NATO officials familiar with the conversations said the principal reasons cited by government leaders for their assent were the need to stave off a humanitarian catastrophe and to fulfill NATO's declared commitment.

"To walk away now would destroy NATO's credibility," British Prime Minister Tony Blair told the House of Commons today.

French Foreign Minister Hubert Vedrine said he was satisfied that every possible means of finding a peaceful resolution had been exhausted. Given the intransigence shown by Yugoslav President Slobodan Milosevic after so many appeals, he indicated that France supported the view that there was no alternative to airstrikes.

The apprehensions within Italy's left-leaning government were compounded recently when a U.S. military court exonerated a Marine pilot whose plane sliced through a ski-left cable during a training flight in northern Italy last year, killing 20 people.

But Foreign Minister Lamberto Dini told the Italian Senate today that Rome now believes NATO has no other choice but to proceed with offensive air operations.