This chapter is concerned with the argument that the major parties have combined since the 1970s to make conditions for minor parties increasingly difficult. More particularly it is concerned with establishing whether the emergence of Pauline Hanson's One Nation can be understood as representing a revolt against all of this; a central correlate of the cartel model is that it should. To see whether the theory of the cartel illuminates the Hanson phenomenon the chapter considers both the extent to which the parties have behaved as a cartel, and the nature of the One Nation challenge, across each of the domains covered by Katz and Mair: ideological, electoral and organisational. It argues that the cartel thesis does not offer a persuasive account of the political conditions that gave rise to One Nation or of the hurdles the new party had to face. More generally, the chapter casts doubt on the validity of the thesis when applied to developments in the Australian party system.