This.I think Estonia, Latvia and Lithuania would be somewhat worried if NATO broke up.
Poland is somewhat too much EU-back garden for Russia to dare attack anytime soon though.
The situation in Ukraine spells trouble for the Baltic states, whose relationship with Russia have been strained since the break-up of the Soviet Union; if the Russian government is able to invade other countries on the pretext of "defending the Russian minority", then I worry thinking about cities like Daugavpils (Latvia) or Narva Estonia). Although I'm skeptical of Russia's interest in the Baltic states (they're not too strategically important anymore), there has been an increasing tendency in the Russian government to expand its influence.
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