This chapter looks at the pacifists, students, ethnic minorities, religious leaders, women’s organizations, intellectuals, and veterans who were involved in isolationism. Special attention is devoted to the issue of armaments limitations, which many saw as the key to the prevention of war. Some isolationists made the argument that American involvement in internationalism would inevitably lead to a corrosion of civil liberties and even the end of democracy. This led to the “fortress America” idea—that through economic self-sufficiency and a robust navy and air force the United States could avoid foreign entanglements and preserve its democratic institutions. Pacifists, of course, were against any military enhancements, which produced a fracturing of opinion among isolationists.