Why Is the Press Called the Fourth Estate?
Because the press has often played a significant role in shaping the course of politics, and viewed as an important force in government, it has been referred to as the fourth estate in relation to the other three traditional estates of the church, the nobility and the townsmen, or commoners. In 1841, Thomas Carlyle used the term to describe the reporters' gallery in the English Parliament as a "Fourth Estate more important" than the other three estates represented there. The importance of the press in a representative democracy is twofold: it informs the citizenry and also serves as a feedback loop between the government and voters.
In the United States, the term "fourth estate" can be contrasted with "the fourth branch of government," since the traditional "three states of the realm" in the French and English monarchies have no direct equivalents in modern American government. The term "fourth estate," or "fourth power," has also been used to describe a political, institutional or societal force whose influence is not officially or consistently recognized.