In Diplomacy and International Relations, each state looks to maintain or develop strategic advantages for their country.
The United States was no different. During the Cold War, it feared that the Soviet Union could destabilize the United States and its allies to become the supreme power on the globe, making the US weak militarily, economically, and diplomatically.
So, the US worked to fight those fears by developing allies and trading partners around the world while also supporting groups that were fighting groups backed by the Soviet Union.