"Throughout the nation's life, executive orders have allowed presidents to make momentous, unilateral policy choices: creating and abolishing executive branch agencies, reorganizing administrative and regulatory processes, handling emergencies, and determining how legislation is implemented. From the Louisiana Purchase to the Emancipation Proclamation, from Franklin Roosevelt's establishment of the Executive Office of the President to Bill Clinton's authorization of loan guarantees for Mexico, from Harry Truman's integration of the armed forces to Ronald Reagan's seizures of regulatory control, American presidents have used executive orders (or their equivalents) to legislate in ways that extend far beyond administrative activity.