Dahl's purpose of Polyarchy is to determine conditions favor or impede a transformation into a political regime in which opponents of the government can openly and legally organize into political parties in order to oppose the government in free and fair elections. (Dahl (1971) Page 2).
Now considering the political Regime of Nigeria, I can say that it presents a struggle to institutionalize stable governments. In the past Nigeria has vacillated between authoritarian military regimes and democratic civilian republics and has had a variety of federal state and local political arrangements. (O'Neil (2010) page 543). However, over the years Nigerians have developed a number of important components of successful democracy namely the fourth Republic which includes a diverse and vigorous media, an educated and often critical elite, outspoken human rights organizations, a growing middle class and a respected legal profession and judiciary. Hence Nigeria has sought to establish the rules and procedures of an effective democratic regime, although political instability, ethnic disunity and bureaucratic corruptions still persists in Nigeria, like many other democracies in the world. .
On the other hand, despite China's three decades of economic reform and global trends of democratization, the political regime of China remains stubbornly authoritarian. China's historical legacy of over 2,000 years of centralized authoritarian rule has buttressed the current regime. In spite of China's economic liberalization, its Communist party-state retains the essential organization structure that the Chinese communist party adopted from the Soviet Union. Although the reformist leaders in China have embraced the concept of market freedom rejecting Marx's idea, their decision to retain a closed political structure is very much in accord with Lenin's vision of the communist part-state. (O'Neil (2010) page 297).