The vice of the groupist theory is that it conceals the most significant aspects of the system. The flaw in the pluralist heaven is that the heavenly… - Elmer Eric Schattschneider

Political conflict is not like a football game, played on a measured field by a fixed number of players in the presence of an audience scrupulously excluded from the playing field. Politics is much more like the original primitive game of football in which everybody was free to join, a game in which the whole population of one town might play the entire population of another town moving freely back and forth across the countryside.

From the standpoint of party politics the margins within which pressure groups operate are limited. If a group divides equally in an election, its impact is zero.

The scope and bias of the pressure system do not fit easily into the calculus of party politics. First, the pressure system is much too small to play the role sometimes assigned to it. Secondly, the supposed party neutrality of the pressure groups is largely a myth.