World War II and the Cold War convinced US politicians to do which of the following? A. begin funding a large peacetime military to counter foreign aggression
B.
pass legislation to allow European immigrants to work in the United States
C.
prevent President Truman from quickly engaging in military action in Korea
D.
support laws that reduced federal spending on education and federal aid

the name of the theory is landmass theory.

i believe it would influence their own way of understanding things. it shall be a foundation where they can draw or start an argument.   historians are also  scientists that  have their tools of analysis and expertise to unlock a variety of difficulties such as relationships of man, origin, politics, economy, and culture. based on facts and understanding on these areas, they may shade light to extract ideas and develop options to validate a hypothesis or debunk it.