The term ‘Republic’ has been derived from the Latin words res publica, public affair or thing. That concept was in turn loosely equivalent to the classical Greek ta koinonia, common things or property, a term originally applied in the early city-state to the city’s treasure, the public funds, and then by analogy coming to symbolise and denote the common interests. It is a term denoting i. a state not ruled by a monarch or emperor, generally a public interest and not a private or hereditary property; ii. a state where power is not directly in the hands of or subject to complete control by the people, in contrast with a democracy; iii. more loosely, any regime where government depends actually or nominally on popular will.  During the later middle ages there were established some brief-lived local republics, consequent on revolt. But it was in certain city states of Italy that the republic re-emerged as a meaningful designation and form of government. In modern usage of republic which derived the dual ideas, absence of monarchy, and some degree of avowed concern for the common welfare of the state and for public control or participation.
Development of the concept
The concept of republic witnessed several ups and downs as a result of the changed contexts. As a combined idea of absence of monarchy, a realm of public affairs and popular consent or participation first emerged, generally as temporary phenomena in the 17th and 18th centuries. Further during the 19th century the moral significance of the republican idea declined in Europe, where monarchies continued and republics remained the exception. Constitutional government spread in the monarchies, and by the early 20th century the term republic no longer connoted the substance and content of political institutions and practice. After World War II, moreover, the term had still less relevance. In essence the basic classification of government was into constitutional government and dictatorships, a division which corresponded in ethos to the former opposition of republics and monarchy. But gradually contemporary ideas on the issue, Montesquieu in particular gave the idea of democracy as direct and small scale and insisted that democracy was impossible in a larger state which, could be at best a representative republic. These and other related were studied and combined by a number of the founding fathers, and especially by James Madison, who used the term republic i. as a technical designation for representative government as opposed to direct democracy and ii. to insist on the necessity for a system of checks and balances against the dangers of straight majoritarian decision in a legislature elected by majority on a single principle of representation.  The insistence that republic is not synonymous with democracy either as direct democracy or as absolute majoritarian democracy, but rather is synonymous constitutional democracy, is correct in the specific US context.
Democracy through Parliamentary system
Democracy, which is normally implemented through the parliamentary system, is a philosophy of life, art of living, way of thinking, method to organise an egalitarian society and essence of world peace. It meets the needs of a civilized, aware and assertive society.  Political life of a majority of the countries of the world are influenced and governed by democracy. Modern political scientists viewed democracy with varied angles and expressed their perception accordingly. Elitist theory of democracy, propounded by Mosaka and Parretto emphasised upon the fact that important decisions are taken by few influential people only.  While J.A. Schumpeter argued that political leaders in democracy cannot enjoy unlimited power as it is restricted, by the choice of people in elections.  On the other believers of participatory democracy emphasise upon participation of common citizens in democratic process. People act as watch dog to activities of rulers and prevent misuse of power. But there is no denying fact that democracy is desired destination for the political system due to its many positive traits and it is the only accepted form of rule in today’s global world.
However, exercise of absolute and unconditional equal opportunity – liberty – right to vote includes three inseparable and interdependent democratic sub-functions which every participating voter of the constituency/electoral college has to perform at the election. They are : i. to evaluate the candidature of every participating voter including self, of the constituency/electoral college; ii. to select the most suitable voter out of all the participating voters of the constituency/electoral college; and iii. to express his/her choice/selection/nomination through ballot paper or any other media.  As such, an individual participating voter inherently is an ‘evaluator-cum-nominator. In other words, democracy does not imply merely casting ballots into the ballot box. It envisages that the decision to vote would be made on the basis of merit alone, with utmost discretion and prudence, unserved by demagoguery and exhortations, and undeflected by considerations- caste, colour, creed, or any other extraneous factors. Enlightened, informed, and vigilant citizenry is a prerequisite to effective functioning of a vibrant democracy.
State vs. society centric approach
In the context there are two prevalent approaches – state – centric and society – centric. State- centrism is described as the perception that operators of the state system – politicians, bureaucrats, the military, industrialists and representatives play the most decisive roles in the determination of public policies. Such actors influence the structure and content of public policies introduced by the state, which embodies a system of law and government; a structure of offices with jurisdiction over a definite territory in which its citizens are located; and a centre of bureaucratic skills focused on information, calculation and implementation.  It also implies that the state is comprised of essentially of politicians and bureaucrats, since the making of public policy is the responsibility of the former while interpretation and implementation of public policy falls under the jurisdiction of bureaucrats.
In contrast, the society – centric approach treats the state as an entity dependent on society and on social forces. Advocates of this approach argue that causes of decisions about public lie in understanding relationships of power and competition among individuals, groups or classes in society or in their international extensions. In this system the state becomes a representative structure that translates the expressed demands of members of society into policy outputs. According to Blondel a key function of government is to convert suggestions, values and ideas from inputs to outputs. Society is assumed to be comprised of a large number of groups with varying interests and desires that they pursue. The dominant or allied classes eventually influence and shape the processes of the state. In nutshell state – centric and society – centric approaches differ in their emphasis on the values, perceptions and preferences of the state versus those of societal classes and groups in the political decision-making process. However, both are used, in practice, depending on the type of activity sought; the prevailing social, political and economic circumstances; and the time available to accomplish the activity.