In the first half of the twentieth century the threat came from the Europeans;during the Cold War Era, the possible communization of Panama and the Russian influence was the major worry.

• 二十世纪前半美国主要对欧陆强权持有疑虑，冷战期间美国则担心巴拿马的赤化，以及苏联涉入巴拿马运河的安全问题。