A democracy is a political system in which government leaders are elected directly by the wide participation of the people or by their representatives. Democracy differs from totalitarianism in nearly every respect. The foundations of modern democracy go back at least as far as the ancient Greeks. The Greeks tried to practice a pure democracy, one in which all citizens participate freely and actively in the political process. But a pure democracy is more an ideal than a workable system for several reasons. Some people have neither the time nor the desire to get involved in the political process. Also, citizens are less able to participate completely and actively as a population grows and as the barriers of distance and time increase. Finally, leaders in a pure democracy may find it difficult or impossible to form cohesive policies because direct voting can lead to conflicting popular opinion.