<P> The Scottish sociologist Robert M. MacIver noted in The Web of Government (1947): </P> <P> The right is always the party sector associated with the interests of the upper or dominant classes, the left the sector expressive of the lower economic or social classes, and the centre that of the middle classes . Historically this criterion seems acceptable . The conservative right has defended entrenched prerogatives, privileges and powers; the left has attacked them . The right has been more favorable to the aristocratic position, to the hierarchy of birth or of wealth; the left has fought for the equalization of advantage or of opportunity, for the claims of the less advantaged . Defense and attack have met, under democratic conditions, not in the name of class but in the name of principle; but the opposing principles have broadly corresponded to the interests of the different classes . </P> <P> Generally, the left wing is characterized by an emphasis on "ideas such as equality, fraternity, rights, progress, reform, and internationalism," while the right wing is characterized by an emphasis on "notions such as authority, hierarchy, order, duty, tradition, reaction and nationalism ." </P> <P> Political scientists and other analysts regard the Left as including anarchists, communists, socialists and social democrats, left - libertarians, progressives, and social liberals . Movements for racial equality are also usually linked with left - wing organizations . Trade unionism is also associated with the left . </P>

What does right wing and left wing mean in politics