What was the main concern expressed in the Long Telegram sent by George Kennan?

The central concern expressed in the Long Telegram by George Kennan was the persistent threat posed by the Soviet Union and its ambitions, particularly regarding security and the geopolitical landscape. Kennan articulated that the Soviet leadership was inherently antagonistic toward the West, seeking to expand its influence and spread its ideological framework, which he saw as a direct challenge to not just U.S. interests but global stability.

Kennan emphasized the necessity of understanding the Soviets' desire for security and how their perception of encirclement influenced their foreign policy. He argued for a strategy of containment to prevent the spread of Soviet influence, which was fundamentally rooted in concerns over national security and the protection of borders in the context of the Cold War. This concern for security was paramount and became a cornerstone of American foreign policy for decades.

The other options, while related to the broader context of international relations, do not fully encapsulate the main thrust of Kennan’s telegram, which was primarily focused on the security threats associated with Soviet expansionism.