President's rule

On 30 January 1991, the DMK government which had come to power after winning the 1989 assembly election, was dismissed by the Indian Prime minister Chandra Shekhar using Article 356 of the Indian Constitution. President's rule was imposed on Tamil Nadu from 31 January. The reason cited for the dismissal was the deterioration of law and order in the state. The dismissal followed pressure on the Chandra Shekhar government by the Congress and AIADMK to dismiss the DMK government. The Chandra Shekhar government fell in March 1991 after the Congress withdrew its outside support. Fresh elections for both the Indian parliament and Tamil Nadu Legislative Assembly were scheduled for June 1991. ^{[1] [2] [3] [4] [5] [6] [7]}

Unification of AIADMK

The AIADMK which had contested and lost the 1989 elections as two different factions reunited under the leadership of Jayalalithaa in February 1989. The V. N. Janaki Ramachandran faction merged with the Jayalalithaa faction to form a single united party and Janaki retired from politics. The reunited party regained the popular "Two Leaves" symbol of the AIADMK. (The Election Commission of India had frozen the symbol for the 1989 elections due to the split). The united AIADMK was able to prove its strength immediately by winning the elections held for two constituencies -Marungapuri and Madurai East on 11 March 1989. (for these two constituencies elections had been postponed earlier due to technical reasons).The AIADMK then allied with the Congress for the 1989 Parliamentary elections. The AIADMK-Congress alliance won 38 of the 39 Lok Sabha seats in that election routing the DMK-Janata Dal led National Front. ^{[8] [9]}

Formation of PMK

The 1991 elections was the first state elections contested by the Pattali Makkal Katchi (PMK), S. Ramadoss, the leader of the Vanniyar caste organisation which demanded proportional reservation in education and employment based on population ratio of each community – the Vanniyar Sangam converted into a political party and entered electoral politics with the 1989 parliamentary elections. The emergence of PMK cut into the DMK's political base in the northern districts of Tamil Nadu. ^{[6] [10]}

Formation of TMK

In 1991, the Thayaga Marumalarchi Kazhagam (TMK) was formed by the actor-politician Vijaya T. Rajendar after he split from the DMK. Later, some of the second rung leaders of the ADMK including Su. Thirunavukkarasar, K. K. S. S. R. Ramachandran, S. D. Ugamchand, V. Karuppasamy Pandian split from the party. For the 1991 elections they formed a pact with T. Rajendar and contested as TMK candidates. ^{[11] [12] [13]}

Assassination of Rajiv Gandhi

On 21 May 1991, leader of the Indian National Congress and its prime ministerial candidate for the 1991 general elections was assassinated by a LTTE suicide bomber. The assassination took place at a campaign meeting at Sriperumpudur where he was campaigning for the Congress candidate Maragatham Chandrasekar.

Coalitions

The two main political formations in this election were the DMK and AIADMK led fronts. The DMK coalition comprised the Communist Party of India (CPI), Communist Party of India (Marxist) (CPM), Janata Dal (JD) and Thayaga Marumalarchi Kazhagam (TMK). The AIADMK front had only two major parties – itself and the Congress. The AIADMK also backed the ICS (SCS) candidate Sanjay Ramasamy in the Virudhunagar constituency. Several smaller parties like the PMK contested the elections alone. ^{[14] [15]}

AIADMK-led Alliance

No.	Party		Election Symbol	Leader	Seats
1.		All India Anna Dravida Munnetra Kazhagam		J. Jayalalithaa	168
2.		Indian National Congress		Vazhappady K. Ramamurthy	65
3.		Indian Congress		Sarat Chandra Sinha	1

DMK-led Alliance

No.	Party		Election Symbol	Leader	Seats
1.		Dravida Munnetra Kazhagam		M. Karunanidhi	176
2.		Communist Party of India (Marxist)		A. Nallasivan	22
3.		Janata Dal		Sivaji Ganesan	15
4.		Thayaga Marumalarchi Kazhagam		Vijaya T. Rajendar	11
5.		Communist Party of India		P. Manickam	10

Results by Pre-Poll Alliance

Summary of the May 1991 Tamil Nadu Legislative Assembly election results

Alliance/Party		Seats won	Change	Popular Vote	Vote %	Adj. %‡
AIADMK+ alliance		225	+172	14,738,042	59.8%
AIADMK		164	+137	10,940,966	44.4%	61.1%
INC		60	+34	3,743,859	15.2%	56.2%
ICS(SCS) †		1	+1	53,217	0.2%	56.1%
DMK+ alliance		7	-164	7,405,935	30.0%
DMK		2	−148	5,535,668	22.5%	29.9%
TMK		2	−1	371,645	1.5%	31.0%
CPI(M)		1	−14	777,532	3.2%	31.2%
JD		1	+1	415,947	1.7%	28.3%
CPI		1	−2	305,143	1.2%	29.9%
Others		2	-8	2,505,431	10.2%
PMK		1	+1	1,452,982	5.9%	7.0%
JP		0	−4	51,564	0.2%	0.7%
IND		1	−5	390,227	1.6%	1.7%
Total		234	–	24,649,408	100%	–