Communism is a political theory based on equality and public ownership. During the Cold War period, the United States feared the spread of communism and Senator Joseph McCarthy led a period known as McCarthyism where many Americans were accused of being communist sympathizers. This created a climate of fear where people could be investigated, lose their jobs, or be imprisoned for opposing governmental policies or being suspected of communist ties without proof. Parallels have been drawn between McCarthyism and more recent limits on civil liberties following the War on Terror.