Demerits of Proportional Representation Systems:

1. Promotes minority thinking:
Proportional representation systems tend to give representation to multiple political parties in proportion to their vote share. While this ensures a diverse representation, it can also lead to the promotion of minority thinking. In such systems, smaller parties or interest groups that represent a specific section of society may gain significant influence in decision-making. This can result in policies that cater to the interests of a few, rather than the majority. It can also lead to the formation of unstable coalition governments, where parties with contrasting ideologies are forced to work together, which can result in policy paralysis and lack of accountability.

2. Does not give scope for organizing bye-elections:
One of the drawbacks of proportional representation systems is that they do not provide any scope for organizing bye-elections. In such systems, representatives are elected from party lists based on the proportion of votes received by each party. This means that if a representative resigns or dies during their term, there is no provision for holding a bye-election to fill the vacant seat. Instead, the seat is usually filled by the next candidate on the party list. This denies voters the opportunity to directly choose their representative and can lead to a lack of accountability.

3. Decreases the significance of the party system:
Proportional representation systems can also decrease the significance of the party system. In such systems, voters often cast their votes for a party rather than a specific candidate. This can lead to a weakening of the link between voters and their representatives, as the focus shifts towards party loyalty rather than individual merits. It can also result in a decline in the accountability of individual representatives, as they are seen as mere representatives of the party rather than independent voices for their constituents. This can lead to a disconnect between the electorate and their representatives, undermining the democratic process.

In conclusion, proportional representation systems have certain demerits. They can promote minority thinking, limit the scope for organizing bye-elections, and decrease the significance of the party system. However, it is important to note that these demerits need to be weighed against the advantages of proportional representation, such as providing fair representation to all sections of society and encouraging political pluralism.