Third Front in Indian politics refers to various alliances formed by smaller parties at various points of time since 1989 to offer a third option to Indian voters, challenging the Indian National Congress and Bhartiya Janata Party.
National Front (NF) was a coalition of political parties, led by the Janata Dal, which formed India's government between 1989 and 1990 under the leadership of N. T. Rama Rao, popularly known as NTR, as President of national front and V. P. Singh as Convener. The coalition's prime minister was V. P. Singh later succeeded by Chandra Shekhar. The parties in the Front were: Janata Dal at national level, Telugu Desam Party of Andhra Pradesh, Dravida Munnetra Kazhagam of Tamil Nadu, and Asom Gana Parishad of Assam and Indian Congress (Socialist). They were supported from outside by the Left Front and the Bharatiya Janata Party. The Leader of the Opposition, P. Upendra was a General Secretary of the Front at its formation.
In 1991, Jharkhand Mukti Morcha became a part of the Front. TDP split in 1995, with a minority faction siding with N. T. Rama Rao and the majority faction choosing to side with Chandrababu Naidu. The Front collapsed before the Lok Sabha elections of 1996, when NF tried to rope in both DMK and AIADMK, resulting in the DMK walking out. After NTR died of a heart attack in January 1996, Janata Dal stood by Rama Rao's widow Lakshmi Parvathi while Left parties formed an alliance with Chandrababu naidu.
After the 1996 elections, Janata Dal, Samajwadi Party, DMK, TDP, AGP, All India Indira Congress (Tiwari), Left Front (4 parties), Tamil Maanila Congress, National Conference, and Maharashtrawadi Gomantak Party formed a 13 party United Front (UF). The coalition formed two governments in India between 1996 and 1998. The Prime Minister was first from Janata Dal - H. D. Deve Gowda, then later succeeded by I. K. Gujral, after both V. P. Singh, Jyoti Basu and Chandrababu Naidu declined to become PM. Both governments were supported from outside by the Indian National Congress under Sitaram Kesri.Chandrababu Naidu of the Telugu Desam Party served as the convener of United Front.
The Indian general election in 1996 returned a fractured verdict. With the Bharatiya Janata Party (BJP) emerging as the largest party, with 161 of 543 seats, it was invited first to form a government. It accepted the offer, and Atal Bihari Vajpayee was sworn in as prime minister. However, he was unable to muster a majority on the floor of the house, and the government fell 13 days later. At a meeting of all the other parties, the Indian National Congress, with a substantial 140 seats, declined to head the government and along with the Communist Party of India (Marxist), agreed to extend outside support to a coalition with the Janata Dal at its head, named the "United Front". Other members of the front included the Samajwadi Party, Dravida Munnetra Kazhagam, Asom Gana Parishad, Tamil Maanila Congress, Communist Party of India and Telugu Desam Party.
With the approval of the Congress and CPI(M), the sitting Chief Minister of Karnataka, H. D. Deve Gowda, was asked to head the coalition as Prime Minister after V. P. Singh and Jyoti Basu declined. His term was from June 1, 1996 - April 21, 1997. The Congress revoked its support to Deve Gowda amidst discontent over communication between the coalition and the Congress. It compromised to support a new government under I. K. Gujral, who was Prime Minister from April 21, 1997 - March 19, 1998. Following the collapse of his government, fresh elections were called, and the United Front lost power.
In March 2018, Chief Minister of West Bengal Mamata Banerjee and Chief Minister of Telangana K. Chandrashekhar Rao called for a coalition urging all regional parties to form a "Federal Front" for the 2019 Indian general election. While Rao indicated a non-BJP non-Congress coalition, Banerjee avoided a direct answer. subsequently.