Until this period there was a provision of a Prime Ministerial candidate apart from the President of the party. Indira Gandhi took over as president of the Congress (I) in 1978 and also became Prime Ministerial candidate in 1980 election.
Following his assassination, Rajiv Gandhi took over as party president and projected as Prime Ministerial candidate in 1984-85 general elections. He was also the prime ministerial candidate during 1989 general elections. In 1991 general elections, Rajiv Gandhi was the party president and prime ministerial candidate of the Congress.
However, he was assassinated on May 21, 1991 while the election was midway. P.V. Narasimha Rao took over as president of the Congress party and became Prime Minister of a minority government.
In 1996 elections too, P.V. Narasimha Rao was party president as well as prime ministerial candidate. Thus the tradition was established that the Congress president is the automatic official nominee of Prime Ministerial candidate of the party since 1978 when Indira Gandhi took over as president of Congress (I) party.
In Lok Sabha elections of 1998 and 1999, Sonia Gandhi was president of the Congress party and the prime ministerial candidate. On 17th April 1999, Vajpayee government lost the confidence vote by one vote and his government fell. Sonia Gandhi claimed in front of the President R.K. Narayanan that the Congress led coalition under her leadership had support of the majority of the house.
President gave her two day time (up to 21st April 1999) to bring the support letters of her coalition party. It was the last moment U-turn by Samajwadi party who back tracked from its support to Sonia Gandhi-led government because of which she couldn’t form the government.
In 2004 too Sonia Gandhi was the Prime Ministerial candidate of the Congress party being the President of the Party. The party won the election and Sonia Gandhi was about to be crowned as Prime minister. However, there were some events that occurred which are still mysterious, but fact is Sonia Gandhi rejected to be the Prime Minister.
Here it should be noted that Sonia Gandhi after elections rejected the post of Prime Minister. Before that when she became president of the party, Sharad Pawar left the Congress citing his serious objections to the issue of Sonia Gandhi's foreign origin. Thus, Manmohan Singh was selected as Prime Minister by Sonia Gandhi. In 2009 general elections, it was Manmohan Singh who was projected officially as the Prime Ministerial candidate of the Congress.
Had Manmohan Singh not declared that he was not going to be the candidate for Prime Minister's post in 2014, he would have been continued to be the official prime ministerial candidate of the party.
At this moment, Manmohan Singh is no more Prime Ministerial candidate, Sonia Gandhi rejected that post and Rahul Gandhi is not anointed as the Prime Ministerial candidate for 2014 general elections. Thus this is the first time the Congress is going for the Lok Sabha election without projecting a PM candidate in deviation of the long established Congress tradition.
Thus Sonia Gandhi is wrong in saying that Congress has no tradition of declaring Prime Ministerial candidate before general election. Either she doesn't know the real tradition of the Congress or offer an incorrect and weak excuse to protect his son from facing liability of possible Congress decimation in 2014.