Why did the office of Vice President become more important, with more responsibilities, as the twentieth century progressed?

The office of Vice President became more important, with more responsibilities, as the twentieth century progressed mainly due to the following reasons:

1. Evolution of governmental roles and functions: As the scope and complexity of the U.S. government's roles and responsibilities increased, so did the need for greater involvement of the Vice President. Federal bureaucracies, regulatory entities, and national security apparatus vastly expanded during the 20th century, and the Vice President was tasked with helping the President manage this growth.

2. Greater visibility and influence of the office: The media age and advances in communications technology allowed the Vice President to have greater visibility and influence on the political stage. This development made the Vice President a more valuable political asset in terms of exercising influence and projecting the administration's message both domestically and internationally.

3. Increasing role in foreign policy: As the United States became a global superpower in the 20th century, the Vice President was increasingly involved in foreign policy efforts, including representing the United States in international forums, meeting with foreign dignitaries, and carrying out diplomatic missions on behalf of the President.

4. Evolution of the President-Vice President relationship: Over time, many Presidents began to include their Vice President more in the decision-making process, assigning them specific responsibilities and tasks. This was especially true with Presidents like Franklin D. Roosevelt, who relied heavily on his Vice President Harry Truman, and Jimmy Carter, who gave Vice President Walter Mondale significant influence within his administration.

5. Increased focus on presidential succession: The 20th century saw a number of presidents die in office or become incapacitated, which heightened the need for a strong and capable Vice President to be prepared for a seamless transition. The 25th Amendment, ratified in 1967, established procedures for presidential succession and reinforced the significant role of the Vice President in the event of a President's death, resignation, or incapacity.

6. Larger role in legislative affairs: The Vice President's role as President of the Senate expanded in the 20th century, especially with the growth of the federal government and increase in legislation being passed. The Vice President's role in breaking ties and influencing legislation became more important as the political environment became more polarized.

Overall, the office of the Vice President gained more responsibilities and importance in the 20th century in response to the growth and evolution of the United States, both domestically and internationally. As the role of the federal government expanded and became more complex, the Vice President's role in supporting the President, representing the United States abroad, and managing legislative affairs also grew in significance.