The answer is income taxes
"The strong influence and flexibility of Communist ideology" best describes the cause of the cultural revolution lack of idealism.
The correct answer is that the war would cost American lives.
Whenever the United States enters a war, there is also the risk of losing soldiers who are fighting over seas. This is general knowledge for most Americans, as they understand that the individuals who enroll in these services due run the risk of having to fight in potentially dangerous situations. This was no different during World War I, as this situation became a reality for thousands of soldiers.
US land was not rich in much of anything, so it was important to get food and clothing from somewhere.