No event had a more profound effect on Theodore Roosevelt's political career than the assassination of President William McKinley in September 1901. At the age of forty-two, Vice President Theodore Roosevelt took the oath of office, becoming the youngest President of the United States before or since. From the start, Roosevelt was committed to making the government work for the people, and in many respects, the people never needed government more. The post-Civil War industrial revolution had generated enormous wealth and power for the men who controlled the levers of business and capital. Regulating the great business trusts to foster fair competition without socializing the free enterprise system would be one of Roosevelt's primary concerns. The railroads, labor, and the processed food industry all came under his scrutiny. Although the regulations he implemented were modest by today's standards, collectively they were a significant first step in an age before warning labels and consumer lawsuits.

Internationally, America was on the threshold of world leadership. Acquisition of the Philippines and Guam after the recent war with Spain expanded the nation's territorial borders almost to Asia. The Panama Canal would only increase American trade and defense interests in the Far East, as well as in Central and South America. In an age that saw the rise of oceanic steamship travel, the country's sense of isolation was on the verge of suddenly becoming as antiquated as yardarms and sails.

A conservative by nature, Roosevelt was progressive in the way he addressed the nation's problems and modern in his view of the presidency. If the people were to be served, according to him, then it was incumbent upon the President to orchestrate the initiatives that would be to their benefit and the nation's welfare. Not since Abraham Lincoln, and Andrew Jackson before him, had a President exercised his executive powers as an equal branch of government. If the Constitution did not specifically deny the President the exercise of power, Roosevelt felt at liberty to do so. "Is there any law that will prevent me from declaring Pelican Island a Federal Bird Reservation? . . .Very well, then I so declare it!" By executive order in March 1903, he established the first of fifty-one national bird sanctuaries. These and the national parks and monuments he created are a part of his great legacy.