United States security was threatened by wars in Europe in World War I and World War II, and since World War II, its been a National Security priority to insure the safety and stability of Europe. U
That's the official "party line", claiming the US was interested only in maintaining stability and safety in Europe.
In fact, US elites knew they would finish WWII with 6% of global population and 50% of global wealth; virtually everything done since that time has been in service of a "Grand Area" subservient to US domestic needs:
American Foreign Policy
"During World War II, American planners were well aware that the United States was going to emerge as a world-dominant power, in a position of hegemony that had few historical parallels, and they organized and met in order to deal with this situation.
"From 1939 to 1945, extensive studies were conducted by the Council on Foreign Relations and the State Department.
"One group was called the War-Peace Studies Group, which met for six years and produced extensive geopolitical analyses and plans. The Council on Foreign Relations is essentially the business input to foreign policy planning.
"These groups also involved every top planner in the State Department, with the exception of the Secretary of State.
"The conception that they developed is what they called 'Grand Area' planning.
The Grand Area was a region that was to be subordinated to the needs of the American economy. As one planner put it, it was to be the region that is 'strategically necessary for world control.'
"The geopolitical analysis held that
the Grand Area had to include at least the Western Hemisphere, the Far East, and the former British Empire, which we were then in the process of dismantling and taking over ourselves.
"This is what is called 'anti-imperialism' in American scholariship.
"The Grand Area was also to include western and southern Europe and the oil-producing regions of the Middle East; in fact, it was to include everything, if that were possible.
"Detailed plans were laid for particular regions of the Grand Area and also for international institutions that were to organize and police it, essentially in the interests of this subordination to U.S. domestic needs."