The fundamental principle of proportional representation is, every section of the society will get representation in the parliament, in proportion to their population.
Different minorities, who otherwise will go without representation, will get representation according to their strength in numbers.
The main purpose of proportional representation is to secure a representative assembly reflecting with more or less mathematical exactness of the various divisions in the electorate.
First we have to decide what should be the basis for the proportional representation. It can be religion, language, nationality or caste. For example, if in a country, 70 percent of the population belong to religion X, another 20 percent belong to Y and yet another 10 percent belong to religion Z. the total number of seats in the legislature may be proportionally divided in to 7:2:1.
That is, 70 percent of the seats in the legislature will be filled by the candidates belonging to religion X, 20 percent of the seats will be filled by the candidates belonging to religion Y and 10 percent to the total number of seats in the legislature will be filled by the candidates belonging to religion Z.
Eminent political thinkers like J.S.Mill has supported proportional representation. They argue that, a legislature should represent, all the sections of the electorate and no minority should go without any representation in the legislature.
Legislature are compared to maps. One cannot draw a map of a country ignoring any part of the country. All the parts of the country should be included in the map. Similarly, all the sections of the electorate should be represented in the legislature.
The advocates of proportional representation point out that the majority principle is based on the assumption of a biparty system, where there are only two major political parties which compete in the elections. In this biparty system the majority rules and the minority remains in the opposition and criticize the government. But, really speaking in this society there are various section with their own peculiar problems and opinions.
To make the legislature a true mirror of the nation, it is essential that all the sections are directly, and more so proportionately reflected in the legislature. Mill has observed that, 'In any real equal democracy every or any section would be represented, not disproportionately but proportionately. A majority of the electorate would always have a majority of representative but a minority of the electorate would always have a minority of the representatives.'
The supporters of proportional representation further argue that under this system there will not be any necessity to readjust or redraw the boundaries of the constituency to equate the number of electors of electors in the constituency on the basis of increasing population.
Proportional representation is preferable to the majority principle, because, it secures representation for minorities. However, proportional representation also has some demerits. For example, it keeps the division in the society intact and never allows one section freely move with other sections. The majority will never mix with the minority and the minority will never mix with the majority.
Secondly, each minority will tend to organize itself in to a political party. These social divisions will be carried over to the political arena. Tension caused in the social divisions will directly have a bearing on the political parties.
The political parties, which should address the social division, would themselves stand strongly divided. Proportional representation will not promote integration but will only promote disintegration of society.
Thirdly, Democracy is based on the conception of national welfare and a common interest. The idea is that various sectional interests will work out an ultimate compromise. Proportional representation, by widening the area of conflict rather than, bringing a common area of agreement, spells danger for democracy.
Fourthly, it is generally believed that political parties promote national interest rather than sectional interest. Proportional representation substitutes narrow sectional interests for the national welfare.
Fifthly, proportional representation promotes, too many political parties. For example, the Indian society is divided on caste basis. If every caste starts a political outfit, it will only create more problems. Moreover, no political party will get a clear majority in the legislature. Thus, proportional representation leads to political instability.
Sixthly, the vast size of the electoral districts under the system of proportional representation involves a number of difficulties. The intimate connection of the candidate with the constituency is not possible. In India, the systems of proportional representation are followed for the election to he Rajya Sabha, the second chamber of he Indian parliament. The members of the Rajya Sabha are elected by the members of the state Legislative Assembly through proportional representation.
For example, the state of Tamil Nadu has 18 representatives in the Rajya Sabha. They are elected by the members of the Tamilnadu State Legislature.
As per figures available in December 2003, the AIADMK, which holds majority in the Assembly, has 9; the DMK has 7 and the Indian National Congress has two members in the Rajya Sabha in proportional to their strength in the Assembly. A party, which has more membership in the legislature, will have proportionately more number of seats in the Rajya Sabha.