What incident exposed the Soviets military inferiority and led to the buildup of weapons in the US and the soviet union?

The Soviet military inferiority was notably exposed during the 1979 Soviet invasion of Afghanistan, where they faced significant resistance from Afghan guerrilla fighters, leading to heavy casualties and logistical challenges. This conflict highlighted the limitations of Soviet military capabilities and prompted the United States to increase its defense spending and military preparedness, leading to an arms buildup in both superpowers during the Cold War. The event intensified the arms race, as both nations sought to enhance their military technologies and capabilities in response to perceived threats.