When the Soviet Union dissolved, the U.S. government gave assurances to the new Russian government that NATO would not move one inch eastward. That pledge has been repeatedly broken since it was made in the 1990s. From Robert Bridge at strategic-culture.org:
Unlike in 1990, Russia has many options left to itself if NATO ignores its proposal for peace and continues to advance on the former Soviet space.
As NATO continues its mission creep inexorably towards the Russian border, Moscow issued a security proposal to the Western military bloc, which is in fact nothing less than an ultimatum: halt any further eastward military advances or Russia will be forced to act on behalf of its national interests.
The date February 9, 1990 will be forever remembered among historians as a ‘day of infamy’ as far as NATO-Russia relations are concerned. That was the date when U.S. Secretary of State James Baker famously assured Soviet leader Mikhail Gorbachev, during glasnost-era talks on German unification that the Western military bloc would not advance “one inch eastward” towards Russia’s borders.
The level of deception contained in that empty pledge is easily discernible today as NATO membership has exploded since the Cold War times to 30 member states. In 2004, the former Soviet states of Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia and Slovenia joined NATO at the 2004 Istanbul summit; Albania and Croatia became members in 2009, while North Macedonia joined in 2020.
Already, the Western military bloc abuts Russia’s northwestern border in the Baltic States of Latvia and Estonia. But now with the political tinderbox known as Ukraine actively seeking membership in NATO, Moscow has produced what amounts to an ultimatum, where the carrot is simply the preservation of peace among the world’s nuclear superpowers.