AFTER ITS BLOODY revolution of 1989, when the dictator Nicolae Ceausescu and his wife were summarily executed, not many people expected that Romania would soon become a functioning democracy. Neighboring Bulgaria, home to a secret police that had staged assassinations in Western European capitals and allegedly plotted to kill the pope, seemed equally unpromising. For the Baltic states of Lithuania, Latvia and Estonia, mere survival was at issue; when the Soviet Union collapsed, the three had only a scant and discouraging modern history as independent states. That all these countries, together with Slovakia and Slovenia, are today to be offered membership in the North Atlantic Treaty Organization is something of a marvel, and cause for celebration. All are now working democracies with free-market economies; human rights are respected, and living standards are steadily growing. The grim austerity and brutal, sometimes murderous regimes of only 15 years ago are now a surprisingly distant memory, hardly real to university students in Bucharest and Sofia and Bratislava. NATO's new members offer evidence that political and economic freedom can take root quickly in this age of globalization, even in seemingly unpromising places; they are an answer to those who now argue that no such liberalization is possible in the Muslim world.

These success stories are also a testimony to the value of NATO at a time when the alliance is being questioned on both sides of the Atlantic. To a large extent, NATO has provided the framework under which the formerly Communist nations of Europe have democratized. Eager for the security offered by a military alliance with the United States, and anxious to be accepted as members of the West's most exclusive club, governments across the region have willingly accepted years of political tutelage. To satisfy NATO, press freedoms have been guaranteed, elections held and potentially explosive problems with ethnic minorities defused; Soviet-style military and police apparatuses have been systematically dismantled. There are still problems, particularly of corruption -- but then, the seven new NATO members have agreed to be bound by "membership action plans" with the alliance for several more years.

Some critics argue that, in the course of carrying out this work of political incubation, NATO has ceased to be a workable military alliance and now may be destined to wither. In fact the organization has been slowly but steadily rebuilding itself for the 21st century. The creation of a reaction force capable of deploying around the world, also to be approved at today's Prague summit, is a significant step in the right direction. Whether NATO now becomes a force for combating terrorists and rogue states and for spreading democracy beyond Europe will depend on whether the political will for a strong transatlantic partnership can be sustained, both in Washington and in Europe. Yet the power and potential of that bond ought to be evident in the two great achievements for which NATO can now be credited: first the deterrence of Soviet aggression and now the consolidation of a Europe that is peaceful and free.