Thanjavur, which sent many stalwarts to Lok Sabha, was a constituency in which former Prime Minister Indira Gandhi once wanted to contest. It was during 1979, some weeks before the fall of the Janata Party government, that Thanjavur had a by-election. This was necessitated as S.D. Somasundaram, who won the seat on AIADMK ticket in 1977, had become a State Minister a year later. Indira Gandhi, who headed the Congress (I), as it was known then, wanted to get back to the Lok Sabha at the earliest possible opportunity. This was after she was expelled from the House immediately following her spectacular victory in the Chickmagalur by-election in Karnataka in late 1978.
In the middle of May 1979, the AIADMK decided to have an electoral alliance with the Congress to fight the by-elections in Thanjavur and Nagapattinam. While Thanjavur was given to Congress (I) the other seat went to the AIADMK. Even though Indira Gandhi had not publicly committed herself to contest from Thanjavur, the State Congress (I) had been urging her to enter the fray. When the announcement was awaited, the then Chief Minister and the AIADMK founder M.G. Ramachandran had saidthat if Indira Gandhi contested, it could give rise to a “serious law and order problem.”
Eventually, the Congress (I) decided to field a lesser known S. Singaravadivelu. The Congress (I) won Thanjavur hands down but it changed equations with the AIADMK.