Downs Economic Theory of Democracy:

Downs Economic Theory of Democracy is a behaviouristic theory based on the behaviour of politicians, political parties and citizen-voters in a democracy.  Downs has emphasized on the "Self-Axiom Principle".  There is difference between selfishness and pursuance of self-axiom principle.  In the case of self-axiom principle unlike selfishness an individual gives an impression to the other party as if he is the well-wisher but at the same time keeps the objective for the maximization of his gain which other do not know.
 
In a democratic country being guided by the self-axiom principle, political parties in general and the ruling party in particular try to lengthen its rule, to be more powerful, and more influential thereby maximizing income and wealth.  Therefore the ruling party pursues policy to win election rather than winning election to pursue policy.  All political parties including the ruling party  try to impress the voters at the time of election in a democracy through their manifestos.  According to Anthony Downs, ruling party tries to maximize votes for winning the election.  It is known as the basic hypothesis in Downs Economic Theory of Democracy. 

Pursuing the self-axiom principle citizen-voters support that political party, which they feel, will pursue policy in line with their preference.  Public policy in Downs Economic Theory of Democracy usually refers to the Budgetary Policy (that is, the Expenditure Policy and the Taxation Policy).  Therefore, to maximize votes the ruling party pursue the budgetary policy in such a way that the marginal votes gained due to expenditure policy will be equal to the marginal vote lost due to the taxation policy. 

It is very difficult to identify the exact  point where the marginal vote gained is marginal vote lost.  It is not feasible.  Again in a democracy maximization of votes is neither the necessary nor the sufficient condition.  If there is direct democracy the ruling party has to secure the majority votes in the election to continue its rule.  In a two-party system of democracy if any political party secure 50% +1 votes it can form the government.  In the case of a multi-party system a party can form the government even securing less than 50%  of votes. However it depends on rule. In a country to form the government if necessarily more than 50% of votes is  required and if any single party cannot fulfill this requirement  in a multiparty system it has to form coalition with some other like-minded parties to show that it has conformed to the condition of more than 50% of votes gained for forming the government.

Therefore maximization of vote is not the necessary condition for winning the election.  In the case of a representative democracy number of votes does not determine but the majority number of elected representatives determine which party will form the government.  Therefore securing maximum  votes to form government is not the necessary condition for a political party. 

The following table also explains that maximization of votes is even not the sufficient condition for any  political party to come to power forming the government. 

Let us assume that there are two political parties X and Y contesting in the election. 

There are seven constituencies and in each constituency there are seven voters, voters being uniformly distributed in all the seven constituencies.

It is evident from Table 6.4 that party X  gets 16 votes and wins in 4 out of the 7 constituencies whereas party Y gets 33  votes but only wins in 3 out of the 7 constituencies.  It results in the majority number of representatives in the parliament from party X.  Therefore party X forms the government.  Even though party Y secures maximum (i.e. 33) votes in this case it cannot form the government. It explains a situation to impress upon that maximization of votes is even not the sufficient condition for winning the election and to form the government. 

In order to continue its rule the ruling party needs to achieve majority votes in the case of direct democracy and majority number of seats in the parliament where representative democracy prevails.  In both the cases majority implies median voters.  The preference of median voters is to be  satisfied as it coincides with the public choice.  However it is very difficult to identify the median voters because most of the citizens feel alienated due to the ineffectiveness of governance.  Even if it is possible to identify the median voters there is no certainty whether they participate in voting due to the inclusion of socio-economic cost.  Besides this, voters behave in a different manner individually at the time of casting their votes to the way they behave when they are in a group.
 
In view of the above reason political parties in general and the ruling party in particular tries to develop vote banks by impressing different pressure groups, passionate minorities on the basis of caste, creed and religion. Ruling party gives priority to the demand of politically sensitive group in one extreme and try to favour different pressure groups on the other extreme through the pursuance of its policy and it results in the misrepresentation of public choice for the maximization of social welfare through the implementation of public policy in a democratic country, which is also a welfare state.