Final answer:
Roosevelt might have chosen to compare the Universal Declaration to other foundational documents from other countries primarily to highlight similarities and shared values among nations and promote a global standard for human rights.
Step-by-step explanation:
Roosevelt might have chosen to compare the Universal Declaration to other foundational documents from other countries primarily to highlight similarities and shared values among nations. By doing so, he aimed to promote a global standard for human rights and emphasize the universality of these rights. Comparing the Universal Declaration to other documents would also help to emphasize the uniqueness of the Universal Declaration.