Ratifying the transformation of three former Soviet bloc nations, NATOwelcomed Hungary, Poland and the Czech Republic as new members in a ceremony that recalledthe alliance's tumultuous beginnings nearly 50 years ago.

Shortly after noon Friday, the three nations' foreign ministers, alongwith a beaming U.S. Secretary of State Madeleine Albright, signed the instruments ofratification on a small stage at the Harry S. Truman Library.

"Hallelujah!" exclaimed Albright, a native of Czechoslovakia,who as a youngster fled Nazi and then communist rule in her native land.

Like Poland and Hungary, Czechoslovakia was a stalwart Warsaw Pactmember just a decade ago. All three have since embraced democracy - and now NATO.Czechoslovakia split into the Czech Republic and Slovakia in 1993.

With foreign ministers Jan Kavan of the Czech Republic, Janos Martonyiof Hungary and Bronislaw Geremek of Poland seated behind her, Albright said, "Neveragain will your fates be tossed around like poker chips on a bargaining table."

"You are truly allies; you are truly home." It was a themerepeated by the three foreign ministers. "We are back in the family!" exultedMartonyi. "We are the closest of allies in our greatest endeavor - the quest forpeace and prosperity."

Geremek said, "Today we celebrate the end of the bipolar worldsymbolized by the Iron Curtain. ... Another curtain must never descend on Europe."Winston Churchill coined the term "Iron Curtain" in a 1946 speech at WestminsterCollege in Fulton, Missouri, in which he warned of postwar Soviet expansion.

"Today is a great day for Poland," Geremek said. "Polandis no longer alone in the defense of its freedom."

Kovan praised the American role in helping to contain the Soviet Unionduring the Cold War. "We, the Central Europeans, will remember what the United Stateshas done for the Old Continent. ... We will never again become a powerless victim of aforeign aggression."

The table used for the signing ceremony was the same one used byPresident Truman on March 12, 1947 - 52 years ago Friday - to sign legislation thatprovided assistance to Greece and Turkey. Both were then facing possible communisttakeovers.

That legislation was one of many steps that led to the formation of theNorth Atlantic Treaty Organization two years later under Truman's leadership. The alliancegrew from its original 12 members with the addition of Greece and Turkey in 1952, Germanyin 1955 and Spain in 1982.

After the signing, military officers from each of the three new membersplaced their respective flags on the right-hand side of the stage, joining those of the 16previous ones. The crowd of several hundred assembled in the library auditorium erupted inapplause.

President Clinton welcomed the new members, saying their presence willmake the United States safer and NATO, stronger. "For years they struggled withdignity and courage to regain their freedom," he said from afar. "And now theywill help us defend it for many years to come."

Many Russians - and some Americans - are wary about the eastwardexpansion of NATO. Russian Foreign Minister Igor Ivanov calls it "a movement in thewrong direction."

"All European states must cooperate in creating a joint securitysystem," he says. "All European states must work together in the interests ofall countries rather than of separate groups." Other critics, including MichaelMandelbaum of the Johns Hopkins School of Advanced International Studies, contend thatNATO expansion risks alienating Russia and could preclude closer ties with Moscow.

But Albright predicted NATO enlargement will continue. "NATOenlargement is not an event; it is a process," she said. "Steadily andsystematically, we will continue erasing without replacing the line drawn in Europe byStalin's bloody boot."

The Clinton administration has said that even Russian membership inNATO should not automatically be ruled out.

But the three foreign ministers, asked about that possibility while enroute here aboard Albright's plane, remained silent.

After a long pause, Hungary's Martonyi said, "Silence is youranswer."

Other hopefuls waiting in the wings for the next round of enlargementare Slovenia, Romania, Bulgaria, Slovakia, Lithuania, Estonia and Latvia. That issue willbe discussed at a NATO summit in Washington next month.