NATO MEETS in Prague this week in expectation that it will ratify expansion of the 19-member alliance to include seven formerly communist nations in Eastern Europe in a bid to preserve its relevance in an age of international terrorism.

But the relevance of NATO and its expansion is about much more than short-term military plans. It's about the long-term integration of security and democracy.

To maintain international support for the war on terrorism, the Bush administration needs to convince other countries that the United States doesn't see its security in conflict with their democratic aspirations. The U.S. embrace of autocracies across the Middle East, its tilt toward Iraq in the 1980s and its current support for Gen. Pervez Musharraf's government in Pakistan lend credence to these fears.

NATO, unlike so many military alliances in history, is anchored in democratic principles as well as short-term strategic calculations. As a result, in the past five decades it has helped create the longest era of peace in European history. It ended the bloody conflicts between France and Germany. And it created the secure environment that allowed the European Union to flourish.

President Bill Clinton launched the expansion of NATO to Eastern Europe with the explicit goal of consolidating democracy, as well as peace, across Europe. And it has worked. By requiring new members to be democratic internally, not just cooperative externally, this policy has accelerated democratic development in formerly communist countries.

This improves U.S. security in several ways.

First, democratic nations are much less likely to be threats to peace. Second, they are less likely to fear their NATO neighbors, both because they also are democracies and because military cooperation within NATO builds trust. Third, by sharing values as well as interests, NATO members have stronger bonds than members of other alliances.

This year's NATO expansion has one other important, valuable aspect. By including Romania and Bulgaria, both nations with Christian Orthodox majorities, NATO is making a powerful statement that democracy is not just for Western Christians. The other five invitees (Estonia, Lithuania, Latvia, Slovenia and Slovakia) have predominantly Roman Catholic and Protestant populations.

Most Americans are only vaguely aware of the schism of Christianity in 1054. This history is better known in Europe, and more relevant. The war between Croats (Roman Catholics) and Serbs (Orthodox) in the early 1990s is simply the most tragic recent example.

Since 9/11, there has been much talk of the potential clash between Christian and Islamic civilizations. But the author of the clash theory, Samuel P. Huntington, focused as much attention on the potential divide between Orthodox and Western Christians. In his 1996 book The Clash of Civilizations, he tied the Orthodoxy to Islam and against the Catholic and Protestant countries of Western Europe and America.

"Where does Europe end?" he asked. "Europe ends where Western Christianity ends and Islam and Orthodoxy begin."

Of course, the religious traditions that flowed from the Great Schism between Eastern and Western Christianity were not on the list of NATO criteria. But looked at from the Orthodox world, NATO has only one Orthodox member (Greece). Its recent additions (Poland, Hungary and the Czech Republic) are all nations with Roman Catholic or Protestant majorities. And, in 1999, NATO's first military action was against an Orthodox-majority country (Serbia).

So the inclusion of Romania and Bulgaria in this round of NATO expansion sends a positive message to the Orthodox world -- in Russia, Ukraine, Macedonia and Serbia, as much as in Romania and Bulgaria.

NATO will emerge from the Prague summit stronger than it entered. Much of the reason will be that it is helping expand the zone of democracy and making clear that, at least in Europe, America sees that goal as reinforcing its own security.

Jim Rosapepe was U.S. ambassador to Romania from 1998 to 2001 and serves on the boards of several investment funds active in Central and Eastern Europe.