India is the world's most populous democracy. A parliamentary republic with a multi-party system, it has six recognised national parties, including the Indian National Congress and the Bharatiya Janata Party (BJP), and more than 40 regional parties. The Congress is considered centre-left or "liberal" in Indian political culture, and the BJP centre-right or "conservative". For most of the period between 1950—when India first became a republic—and the late 1980s, the Congress held a majority in the parliament. Since then, however, it has increasingly shared the political stage with the BJP, as well as with powerful regional parties which have often forced the creation of multi-party coalitions at the Centre.
In the Republic of India's first three general elections, in 1951, 1957, and 1962, the Jawaharlal Nehru-led Congress won easy victories. On Nehru's death in 1964, Lal Bahadur Shastri briefly became prime minister; he was succeeded, after his own unexpected death in 1966, by Indira Gandhi, who went on to lead the Congress to election victories in 1967 and 1971. Following public discontent with the state of emergency she declared in 1975, the Congress was voted out of power in 1977; the just-created Janata Party, which had opposed the emergency, was voted in. Its government lasted just over three years. Voted back into power in 1980, the Congress saw a change in leadership in 1984, when Indira Gandhi was assassinated; she was succeeded by her son Rajiv Gandhi, who won an easy victory in the general elections later that year. The Congress was voted out again in 1989 when a National Front coalition, led by the newly formed Janata Dal in alliance with the Left Front, won the elections; that government too proved relatively short-lived: it lasted just under two years. Elections were held again in 1991; no party won an absolute majority. But the Congress, as the largest single party, was able to form a minority government led by P.V. Narasimha Rao.
The two years after the general election of 1996 were marked by political turmoil. Several short-lived alliances shared power at the Centre. The BJP formed a government briefly in 1996; it was followed by two comparatively long-lasting United Front coalitions, which depended on external support. In 1998, the BJP was able to form a successful coalition, the National Democratic Alliance (NDA), which under the leadership of Atal Bihari Vajpayee, became the first non-Congress government to complete a five-year term. In the 2004 Indian general elections, again no party won an absolute majority, but the Congress emerged as the largest single party, forming a successful coalition: the United Progressive Alliance (UPA). It had the support of left-leaning parties and MPs opposed to the BJP. The UPA coalition was returned to power in the 2009 general election with increased numbers, and it no longer required external support from India's Communist parties. That year, Manmohan Singh became the first prime minister since Jawaharlal Nehru in 1957 and 1962 to be re-elected to a second consecutive five-year term.