Estonia, Lithuania and Latvia are among seven former Soviet bloc countries formally joining NATO on Monday

When Belgian warplanes streak over the three Baltic states this week, there will be rejoicing on the ground. Estonia, Lithuania and Latvia are among seven former Soviet bloc countries formally joining NATO on Monday, and they are realizing a long-denied dream - entering a military alliance by choice instead of by coercion. "It's good to know someone up there will be keeping bad guys away from our country," said Aurimas Sirvinskas, a 27-year-old salesman in Lithuania, referring to the NATO F-16s that will soon begin flying out of Lithuanian bases. Who are the "bad guys"? No one says officially now that the end of the Cold War and collapse of communism have taken away the Soviet Union as NATO's foe. But many Balts point to Russia, which is resented for the forcible inclusion of the Baltic states into the Soviet Union in 1940. The Kremlin, in turn, is leery of the expansion of NATO. And it is particularly angry over the alliance's inclusion of the three neighboring Baltic states, saying they should have been a no-go area for NATO. Over the centuries, the Baltic states have been sucked into one power bloc or another. Their formal acceptance into NATO at a ceremony in Washington on Monday marks the first time in modern history that they have freely joined a military alliance. Just 15 years ago, they appeared firmly rooted in the Soviet bloc, with more than 100,000 Red Army soldiers at hundreds of bases and airfields here. Then as the Soviet Union fell apart in 1991, Estonia, Latvia and Lithuania shrugged off five decades of occupation and regained independence. Lithuania's prime minister, Algirdas Brazauskas, sees NATO membership as a treasured milestone for his nation.