Final answer:
The Nineteenth Amendment was necessary due to various conditions that preceded it, including the efforts of suffragists, the influence of World War I, and tensions within the suffrage movement.
Step-by-step explanation:
The Nineteenth Amendment, which prohibited voter discrimination on the basis of sex, was made necessary by several conditions that preceded it. Some of these conditions include the efforts of suffragists like Carrie Chapman Catt and Alice Paul, who put pressure on Congress to pass the amendment. World War I also played a role in fueling support for women's suffrage, as suffragists saw it as a way to demonstrate that the war was a war for democracy. Additionally, there were tensions between different suffrage organizations and conflicting views on previous amendments, such as the Fourteenth and Fifteenth Amendments.