This chapter uses the concept of structure of competition to open up possibilities of distinguishing between different party systems. It highlights how strategic actions by parties help maintain and sustain particular characteristics of a party system. The chapter examines how the regionalist–nationalist issue dimension potentially limits the Bharatiya Janata Party (BJP) room to manoeuvre. It focuses on how the particular structure of competition in the states of Odisha, West Bengal, Andhra Pradesh, Tamil Nadu and Kerala has constrained the BJP's growth and development. Traditionally, the main competition in Odisha, Andhra Pradesh and West Bengal was between the Congress and the Biju Janata Dal, Telugu Desam Party and the Communist Party of India, respectively. The emergence of the BJP as a key third party in the 1991 and 1996 Lok Sabha elections damaged the prospects of the key state-based players in the three states.