Evolution of the Indian party system

The Indian party system has gone through various phases after the country’s independence from the British rule in 1947. It began with a phase of Congress’ dominance during the first two decades after India’s independence 4. The Congress party was formed in 1885 and led India’s independence movement against the British rule. After 1967, Congress’s dominance declined due to various reasons including increased competition and emergence of anti-Congress alliances in many states although the party continued to be the principal national party in the country. The period after 1989 was marked by further decline in Congress’ prospects, growing influence of regional parties in many states and the emergence of the Bhartiya Janata Party (BJP) as the main challenger to the Congress at the national level 5, 6. The BJP was formed in 1984 and was the successor party of the Bhartiya Jana Sangh, formed in 1951. The fragmentation of the Indian party system after 1989 also saw national and regional parties forging alliances to improve their electoral prospects and forming coalition governments at the centre and in many states7, 8.

The 2014 Lok Sabha election was an important milestone in Indian politics and the party system when, for the first time since 1984, a single party, in this instance the BJP, was able to win a majority of seats. It was also the first time that a party other than the Congress had achieved this feat. After BJP’s victory in 2014, many opposition parties attempted a strategy to form alliances for the 2019 election with the aim to defeat the BJP. An important premise behind these efforts was that the BJP’s victory in 2014 was achieved based on a relatively small (31%) percentage of votes and therefore, if the remaining 69% of the votes were consolidated in favour of a united opposition, the BJP could be defeated. However, these efforts were not particularly successful due to competing interests and demands of various opposition parties and the personal political ambitions of their leaders.

A divided opposition in conjunction with Modi’s popularity helped the BJP to achieve another majority victory in the 2019, improving both its tally of seats and vote share, which prompted suggestions that the BJP had emerged as the new dominant party 9, 10. An all India post-2019 election survey conducted by the Centre for the Study of Developing Societies (CSDS) found that 46.5% of the respondents preferred Modi as India’s Prime Minister 11. In the same survey, 41.2% of the respondent reported being ‘particularly close’ to the BJP followed by the Congress at 19.2% 11. Ziegfeld notes that the presence or absence of alliances in 2019 had a modest impact on the election outcome ¹² .

In the recent Lok Sabha elections, the BJP won majority of seats in 2014 (51.9%) and 2019 (55.8%) based on a relatively low vote share of 31.3% and 37.7% respectively. The Congress was the distant second party, securing 19.7% and 19.3% vote share and a much lower 8.1% and 9.5% seat share, in 2014 and 2019 respectively. The balance of the votes and seats were secured by several other (mainly regional) parties, thus producing a national party system dominated by the BJP. The disproportionality between the vote and the seat share resulted in a substantial ‘seat bonus’ (seat share less vote share) for the BJP – 20.6% in 2014 and 18.1% in 2019, demonstrating the workings of the Single Member Plurality electoral system (SMPS) in India.

To counter a party in power or a dominant party, opposition parties have, on many occasions, formed alliances to minimise splitting of their votes. This means that parties in a pre-election alliance agree to contest elections only in certain seats with an aim to aggregate support behind the alliance candidate in a constituency, thereby maximising the likelihood of winning 12 . The most prominent example of this was in the 1977 Lok Sabha election, where a large number of opposition parties amalgamated under a common party label (Janata Party/Bharatiya Lok Dal) to defeat the Congress, winning 41% of the votes and 54% of the seats. This also led to a substantial reduction in the effective number of parties (ENP), a key measure, which is calculated by weighing the contesting number of parties by their respective vote 13. The ENP of 2.1 in 1977 has been the lowest during the Lok Sabha elections conducted in India since independence 14. The emergence and success of the BJP in the 1990’s has also been attributed, in part, to its pre-election alliances to counter the Congress 15. Since the fragmentation of the Indian system after 1989, parties have increasingly resorted to forming pre-election alliances to improve their electoral prospects both in the national and state assembly elections, with coalition governments becoming the norm at the national level and in many states.

As we approach the 2024 Lok Sabha election, many opposition parties have again initiated efforts to form state by state alliances with an objective of having a united opposition candidate in most of the constituencies to defeat the BJP. This paper argues and provides evidence that the prospects and challenges of the opposition parties to succeed in this initiative need to be studied in light of the dynamics of constituency level electoral competition in India.

Constituency level analysis

Although understanding macro level trends, and the vote and seat share of parties at the national level as discussed in the previous sections is useful, this does not provide granular details about the nature of party competition at the constituency level, where elections are actually contested. For example, whilst the BJP secured an aggregate vote share of 31.0% and 37.7% in 2014 and 2019 respectively, its vote share varied considerably across various consistencies. Therefore, it is important to analyse constituency level data to assess the challenges and opportunities for a united opposition unity to succeed in defeating the BJP in the 2024 Lok Sabha election.

Index of Opposition Unity (IOU)

An ‘Index of Opposition Unity’ (IOU) has been formulated to represent the relative fragmentation of the opposition votes 16. This is expressed as the ratio of vote share of the largest opposition party to the total vote share of all the opposition parties. Thus, a high value of IOU indicates greater opposition unity.

Figure 1 shows that the average IOU at the constituency level for the Lok Sabha elections during 1952-2019 ranged between 0.61 and 0.85. During the phase of Congress’ dominance, the IOU remained between a narrow range of 0.62-0.66 (ignoring the 1957 election) indicating a relatively fragmented opposition. 1977 saw the IOU reaching its highest level of 0.85 when a large number of opposition parties amalgamated to defeat the Congress. This was followed by a steep decline in IOU in 1980 to 0.66 with the Congress returning to power, but it increased to a relatively high level of 0.75 in 1984 election which saw Congress securing a major victory in the aftermath of the assassination of Prime Minister Indira Gandhi. With the advent of coalition politics in India in the 1990s, the IOU fell in 1991 to 0.65 and 0.61 in 1996 before rising again within a narrow range of 0.70-0.73 in the next three elections during 1998-2004, as coalition governments became the norm at the national level. However, the IOU fell again in 2009 to one of its lowest levels at 0.63.

In 2014, when the BJP won a majority of seats, the IOU remained around the same level as in 2009 but rose substantially to 0.75 in 2019. This was mainly because of the anti-BJP alliances in Uttar Pradesh and Karnataka, which led to aggregation of most of the non-BJP votes behind a single candidate in each constituency 18. The average IOU for the constituencies won by the BJP was 0.64 in 2014 but rose to about 0.80 in 2019. Despite the increase in IOU, the BJP increased its tally of seats and vote share in the 2019 election. Chhibber notes that the IOU has many limitations, and it does not provide insights into the relative importance of the strength of the winning party versus the split in opposition votes in determining the election outcome 19. Thus, whilst IOU is a useful measure, it cannot fully assess the prospects of the winning party.

BJP’s winning vote share

Figure 2 provides the distribution (histogram) of the BJP’s vote share in the constituencies it won in the 2014 (282) and 2019 (303) Lok Sabha elections. As can be seen, in 2014, the BJP won most of its constituencies with vote share ranging from 40%-60%. In 2019, the distribution of the winning vote share for the BJP shifted towards the right with a higher number of constituencies won by vote share in the range of 40%-60% and a significant number being won by more than 60% vote share. Further, in 2014 there were a substantial number of constituencies, which were won by the BJP by less than 40% of votes, which is not the case in 2019 indicating a consolidation of votes in favour of the BJP.

Figure 3, Figure 4 provide the distribution of the BJP’s vote at the constituency level in different states in the 2014 and 2019 elections.

Figure 3 reinforces the point that the BJP won most of its seats in 2014 by winning 40%-60% of the votes in many states. In Gujarat and to a lesser extent, Madhya Pradesh, the BJP also won a significant number of seats by a vote share greater than 60%. On the other hand, in Uttar Pradesh, the state with the largest number of seats in Lok Sabha, and to some extent in Bihar, the party won a significant number of seats with a vote share of less than 40%.

Figure 4 shows that in 2019, the distribution of share of votes in the constituencies BJP won, has shifted towards the right for almost all states and the party won most of its seats by vote share of 50%-60%. Although the party won in few constituencies with less than 50% vote share in Uttar Pradesh, most of its wins in the state were secured with vote share of greater than 50%. In West Bengal, where the BJP was able to improve its tally of seats in 2019, the party won 9 seats with a vote share greater than 50%, and the same number with a vote share less than 50%.

Table 1, Table 2 provide a more precise picture of the distribution of seats won by the BJP categorised by vote share in 2014 and 2019 elections respectively.

Table 1 shows that the average vote share of the BJP in all the 282 constituencies it won in 2014 was 49%. Looking at some of the larger states, BJP’s average vote share in 2014 at the constituency level was much higher in Gujarat (59%), Uttarakhand (56%), Madhya Pradesh, Maharashtra and Rajasthan (all 55%) than the overall average, whilst its vote share was much lower than the overall average in several other states: Odisha (34%), Tamil Nadu (38%), West Bengal (40%), Punjab (41%), Jharkhand and Jammu & Kashmir (both 41%), Bihar (42%) and Uttar Pradesh (44%). The BJP won 129 of its 282 seats (45.8%) with a vote share greater than 50%, of which 29 were won with greater than 60% vote share. The party won 153 seats (54.2%) with vote share of less than 50%, most of these being won by a vote share of 40%-50%. In Uttar Pradesh, the party won 18 of the 71 with a relatively low vote share of 30-40%. Only in Jammu and Kashmir, the BJP won one of its three seats with less than 30% of votes.

Table 2 shows the distribution of vote share in the seats the BJP won in the 2019 election. The BJP’s average vote share in 303 constituencies it won increased from 49% in 2014 to 55% in 2019. In terms of the trends in larger states, BJP’s average vote share at the constituency level in 2019 was much higher than the overall average in the states of Himachal Pradesh (69%), Gujarat and Uttarakhand (both 62%) and Rajasthan (61%). In many states, the party’s vote share at the constituency level was still higher than 50% but closer to the overall average of 55%. These included Haryana (58%), Madhya Pradesh (58%), Bihar and Jharkhand (both 56%), Assam and Karnataka (55%), Uttar Pradesh (53%) and Chhattisgarh (52%). Only in few states, the average vote share of the BJP was below 50%. These included West Bengal (48%), Punjab (47%), Odisha (42%) and Telangana (41%). These trends meant that in aggregate, the BJP won a sizeable i.e. 217 of 303 or 71.6% of seats with a vote share greater than 50%, of which 92 (30% of the total seats) were won with greater than 60% vote share. It won 58 (19.1%) seats with vote share 45%-50%, 21 (6.9%) seats with vote share 40%-45% and only 7 seats (2.3%) with vote share of 30%- 40%. So, in total the party won only 86 seats with less than 50% vote share, and it is important to focus on these more competitive constituencies to assess the prospects of a united opposition.

Nagayama diagram

Nagayama diagram is a useful tool to visualise how competitive the party system is at the constituency level 20. It plots the vote share of the winning party (V1) against the vote share (V2) of the runner-up party, which are enclosed within a triangle bound between the two lines characterised by V1-V2=0 and V1+V2=1. An analytical method of further segmenting the different areas of the Nagayama diagram, using the parameter z (0<=z<=0.5) has been used to show the nature of competition at the constituency level, and one can change the value of z to operationalise the meaning of a competitive district 20.

Figure 5 plots Nagayama diagram for the 86 constituencies, where the BJP won with less than 50% vote share in 2019, and where the opposition could, in theory, gain from consolidating its vote in favour of a single opposition candidate in 2024. This is based on the value of the parameter z = 0.20, which is plausible since 80 percent vote share for the top two parties can be seen as a reasonable depiction of a two party competition or dominance 20. Based on this segmentation, area with competitive constituencies is given by H + A + F + G and the area representing constituencies with limited third-party strength is given by H + A + B + C 20.

It shows that these constituencies lie in segments H, G or E. The constituencies falling under segment H are characterised by limited minor party strength and political competitiveness among the top two parties, which means close competition between the BJP and the runner-up party, which provides some scope for a united opposition to defeat the BJP. Similarly, segment E represents constituencies where the BJP and the runner up party are in competition with other parties, but the united opposition will have limited prospects where the BJP share lies close to 50%. However, the opposition may benefit from coming together where BJP’s vote share starts to decline below 50%, which based on a visual examination appears to be the case in only a few constituencies. The area in segment G represents multi-party competition and here again a united opposition can benefit in constituencies where the vote share of the BJP and the runner-up party lie in the range of 40-50%. In segment G, where the BJP’s vote share is greater than 40% and that of the runner-up party less than 40%, there would be limited advantage for the opposition parties to come together to defeat the BJP.

Winning margin and the number of contesting parties

Another useful way to assess the nature of competitiveness at the constituency level is by analysing the BJP’s winning margin (over the runner-up party) in the 86 constituencies won by the BJP with less than 50% vote share. Figure 6 shows that in 39 of these constituencies BJP’s winning margin was less than 5%, whilst in 32 constituencies, BJP’s winning margin was higher (5%-10%), which were therefore less competitive. In the balance 15 constituencies, BJP’s victory margin was in the range of 10%-25%. Thus, it can be argued that the 39 constituencies where the contest was close (winning margin of BJP being less than 5%) offer best prospects for a united opposition to succeed. Another 32 constituencies where the BJP’s winning margin was 5%-10% may also provide some scope for a united opposition to succeed against the BJP.

In addition to the vote share of the winning party, another factor to consider when assessing competitiveness is the number of contesting parties in a constituency. Table 3 shows that in the 86 constituencies where the BJP won with less than 50% vote share in 2019, the number of contesting parties tended to be higher where the BJP’s winning share was also relatively high i.e. 45%-50% and 40%-45% and lower where its vote share was in the range 30%-40%. On this basis, only in the 7 constituencies where BJP’s vote share is less than 40%, there is a better scope for the opposition parties to unite behind a single candidate, due to relatively lower number of contesting parties. Further, of the 86 target constituencies where the BJP won with a vote share of less than 50%, 61 had greater than 10 average contesting parties. This suggests that a united opposition is likely to have lower prospects in these constituencies because of a large number of contesting parties. Overall, this does not paint a very positive picture for opposition unity.

Further, it is useful to study the combined effect of the number of contesting parties and BJP’s victory margin to analyse how this would impact the prospects of a united opposition. Table 4 shows the number of contesting parties in the constituencies won by the BJP with less than 50% vote share and where its winning margin was less than 10%. In theory, these 71 constituencies are the ones the opposition needs to focus on when considering its strategy to consolidate its vote. However, as Table 4 shows, the number of contesting parties in these constituencies across different BJP’s vote share categories was relatively high. This means even in these more competitive 71 constituencies, the opposition will still face a major challenge of reducing the number of contesting parties to avoid wastage of anti-BJP votes.

Table 5 shows that the highest number of these constituencies are in Uttar Pradesh (21) and West Bengal (11), where having a united front is more likely to produce results for the opposition. However, there are many states in this list where opposition unity may not provide any incremental benefit for the opposition where the contest is already mainly between the BJP and a single opposition party or where the regional party may be less agreeable to join an anti-BJP pre-election alliance.