No other office in American government has undergone a greater transformation than the vice presidency. For its first 150 years, it was mostly inhabited by little-known politicians, and served primarily to provide an understudy for the president. As the federal government expanded during the latter half of the twentieth century, so did the responsibilities of the vice president. In just the past decade, this once forgotten office has emerged as one of the most powerful positions in Washington — a trend that is likely to continue in the future.