No wonder these are troubling times for Ukraine, a country of 52 million people that has barely recovered from the surprise of gaining independence in 1991 before discovering that it risks turning into a flashpoint between two new Western and Eastern blocs.
Nato's enlargement clearly seems attractive to governments in the Czech Republic, Hungary and Poland, keen to lock themselves permanently into Western institutions. But for leaders in Kiev the expansion of the Atlantic alliance is a process which, if mishandled, could threaten the integrity and independence of the Ukrainian state itself.
Despite Western assurances that Nato's enlargement will not threaten Russia, President Boris Yeltsin and his advisers have indicated that the Kremlin will react vigorously if Nato goes ahead. Seen from Ukraine, the greatest concern is that Moscow will seek to accelerate the political and military integration of the Commonwealth of Independent States (CIS), the loose association of newly sovereign countries that replaced the Soviet Union.
Under President Leonid Kuchma, and his predecessor, Leonid Kravchuk, Ukraine has opposed closer integration of the CIS, fearing it as a first step to being dragged back under Moscow's control. Leaders took it as a bad sign when Mr Yeltsin issued a decree last September that envisaged the transformation of the CIS into a Russian-led security alliance.
Matters have grown even more serious for Ukraine this year. The Russian parliament's condemnation of the treaty that abolished the Soviet Union was quickly followed by the announcement of a new union between Russia and Belarus, a pro-Russian state which borders Ukraine.
Then Mr Yeltsin postponed a visit to Kiev on the grounds that Ukraine was delaying an agreement on how to divide up the former Soviet Black Sea fleet, based in the Ukrainian peninsula of Crimea. To crown everything, Mr Yeltsin's chief opponent in next June's presidential election in Russia, Gennady Zyuganov, is a Communist who stands for the Soviet Union's restoration, albeit by peaceful means.
Significantly, all these implicit threats to Ukraine's independence have emerged even before Nato has set out a precise timetable for incorporating Poland and other states. Assuming that it eventually announces such a timetable, there are several ways for Russia to tighten the screw on Ukraine.
One is to deploy extra Russian military forces in Belarus. Another is to exploit Ukraine's dependence on Russia for oil and gas. A third point of vulnerability for Ukraine lies in the fact that ethnic Russian majorities who are not noticeably enthusiastic about Ukrainian statehood dominate Crimea and parts of eastern Ukraine.
Mr Yeltsin has avoided playing these cards, but it is easy to imagine a tougher Russian policy in the event of Nato's expansion, especially if the next president in the Kremlin is not a reformer. With Ukrainian nationalism enjoying its strongest support in western Ukraine, there is an obvious risk that Nato's enlargement, coupled with a hardline Russian response, could jeopardise unity.
Faced with this prospect, officials in Kiev say Nato should take the utmost care, when expanding, not to isolate Russia or undermine Ukraine's security. Best of all, according to Deputy Foreign Minister, Konstyantyn Hryshchenko, would be for Nato to transform itself into a "Euro-Atlantic security organisation" that would include Russia and Ukraine.Reuse content