The emergence of APC following the merger of ACN, CPC, ANPP and APGA may have quenched the thirst of most Nigerians of Nigeria practising a clear cut two-party system. Before this time, the ruling PDP held sway in states and the national assembly with what has come to be known as national spread. Other parties were widely believed to be regional and ethnic based. ACN held sway in the Yoruba dominated South West. CPC and ANPP held sway in the north dominated by Hausa/Fulani, Kanuri, and other ethnic groups in the north. In the South East where APGA held sway, however, it was only Governor Rochas Okorocha of Imo State that joined the APC. This trend of ethnic/regional party politics started in the late 1940s when some ethnic based organizations metamorphosed into political parties. In the north, Jam'iyyar Mutanen Arewa metamorphosed into Norther People's Congress (NPC). In the west, Action Group (AG) emerged as the political wing of Egbe Omo Oduduwa. In the east, in 1948, at a Pan-Igbo conference at Aba, the Igbo Federation Union gave birth to Igbo State Union which used its Igbo linguistic domination to make the National Council of Nigeria and the Cameroons its political wing.
This trend also survived into the second republic. In the west Unity Party of Nigeria (UPN) held sway even upto Bendel State. In the east Nigerian Peoples Party (NPP) held sway upto Plateau State. In the north Greater Nigerian Peoples Party (GNPP) held sway to some extent. National Party of Nigeria (NPN), like the Peoples Democratic Party (PDP), held sway in every part of the country (national spread).
With the emergence of the APC, I see PDP being challenged in national spread. The ACN has many members in the north and west, and is wooing people in the south and in the east.