Final answer:
The absence of the United States greatly weakened the League of Nations.
Step-by-step explanation:
The best statement that explains the cartoon's message is c) The absence of the United States from its membership greatly weakened the League of Nations.
The political cartoon depicts a bridge labeled Belgium, France, England, and Italy, with a gap between France and England. Uncle Sam is shown sitting on the England and Italy side, smoking in a reclined position. This symbolizes the absence of the United States from the League of Nations, which weakened the organization's membership and influence.
The U.S. Senate's fear of losing control over declaring war and concerns about Britain and France's control over the League led to the United States not joining the organization. This lack of U.S. participation significantly weakened the League of Nations and its ability to mediate and resolve international disputes.