To understand the current geopolitical scenario in Eastern Europe, it is necessary to analyze the transition of the world order after World War II and the tensions that shaped the border between Russia and the West.
The Balance of Power: NATO vs. Warsaw Pact
After 1945, the world was divided into two major military blocs:
NATO (1949): The North Atlantic Treaty Organization was created by the USA and Western European countries as a mutual defense alliance against the advance of communism. Its central principle is Article 5: an attack against one member is an attack against all.
Warsaw Pact (1955): The Soviet Union's (USSR) response. A military alliance between the USSR and its satellite states in Eastern Europe (such as Poland, East Germany, and Hungary), consolidating Soviet dominance over that region.
1994: The Turning Point and Bill Clinton
With the dissolution of the USSR in 1991, the Warsaw Pact ceased to exist. However, NATO did not dissolve. In 1994, under Bill Clinton's administration, a crucial movement occurred that many Russian analysts consider the "breaking of a verbal promise" made during German reunification (that NATO would not expand "one inch to the east").
That year, Clinton launched the Partnership for Peace, a program that opened the doors for former members of the Soviet bloc to approach NATO. For Russia, this was seen as the beginning of a strategic encirclement.
The Role of Ukraine and the Budapest Memorandum
Also in 1994, the Budapest Memorandum was signed. Ukraine agreed to give up the third largest nuclear arsenal in the world (inherited from the USSR) in exchange for security guarantees and respect for its borders from the USA, United Kingdom, and Russia.
The Proxy War
The Kremlin's perspective is that NATO's expansion, reaching Ukraine's borders, turned the country into a "forward outpost" of the West.
The Geopolitical Siege: According to this view, Washington's interest in including Ukraine in the western sphere aimed to neutralize Russian military capability and remove its natural buffer zone.
The "Proxy War": Russia argues that the conflict is not just between Moscow and Kiev, but a war of the USA/NATO against Russia, using Ukrainian territory and soldiers to wear down Russian power without Western powers needing to send their own troops directly.
The Invasion: "Security Dilemma"
Russia maintains that it was compelled to intervene militarily because the "red line" was crossed. In geopolitical realism, this is called the Security Dilemma: when the increase in security of one side (Ukraine seeking NATO) is perceived as an immediate existential threat by the other (Russia).
For Moscow, the possibility of NATO bases and missile systems on Ukrainian soil would leave Russia vulnerable to an attack without time to react, justifying, from its perspective, the invasion as an act of "preventive self-defense."