After the Cold War came to an end in 1989, the North Atlantic Treaty Organization expanded much faster than many people expected it to. Barely a decade on, Poland, Hungary and the Czech Republic last week formally joined the 16-member alliance. Adding significance to the event is the fact that all three democracies were once satellites of the Soviet Union and members of the Warsaw Pact forces ranged against NATO. Fittingly, the induction ceremony was held at the birthplace of Harry S. Truman, the U.S. president who presided over the birth of NATO in 1949.

After repeated invasions and occupations this century, NATO's newest members see membership in the Western security alliance and the U.S. obligation to defend them as guarantees that they will no longer be threatened in the future. Security does not come cheap, however. While Poland, Hungary and the Czech Republic meet the minimum military requirements of NATO membership, numerous challenges remain, from upgrading aging Soviet-era military equipment to teaching soldiers to speak English, NATO's lingua franca. Military upgrades alone are expected to cost billions of dollars and will place a considerable burden on these countries, which are still struggling to build free-market economies and elevate living standards that fall well below Western European levels.

Despite the challenges that lie ahead, NATO's newest members did not come into the alliance empty-handed, and are eager to show they are more than beneficiaries. Warsaw has indicated its willingness to participate in any NATO peacekeeping mission in the war-torn Yugoslav province of Kosovo. Hungary has offered an engineering battalion to help rebuild bridges in Croatia. The Czech Republic will place its world-class chemical-weapons detection unit at NATO's disposal.