FACTBOX: What happens next in India's confidence vote

(Reuters) - Indian Prime Minister Manmohan Singh faces a confidence vote in parliament on Tuesday, kicking off a debate that will decide the fate of his government and a nuclear deal with the United States.

The Congress-led government needs to secure 272 votes -- if every lawmaker votes -- to win the confidence motion and push ahead with the nuclear deal and any economic reforms.

Here is a look at the possible scenarios, according to India's political experts.

GOVERNMENT WINS

* The Congress party-led ruling United Progressive Alliance (UPA) wins the vote of confidence.

The government continues in power, moves ahead with a civilian nuclear deal with the United States and continues with pending economic reforms. It also gets time to get organized before a general election in May 2009.

THE GOVERNMENT LOSES

* The ruling UPA coalition loses the vote of confidence and the government falls.

The president could ask the prime minister to continue in power as a caretaker government.

The Election Commission of India will then fix a date and an early election will be called, most likely by the end of the year.

OR

The opposition could try to form an interim government before the scheduled May 2009 election. This is an unlikely scenario because the main Hindu nationalist opposition Bharatiya Janata Party (BJP) has said it would prefer elections if the government falls.

A TIE

* The vote of no-confidence ends in a tie and the speaker in parliament casts his vote to decide the outcome. In this case, the government could fall as the speaker, Somnath Chatterjee, a member of the Communist Party of India (Marxist), would probably vote against the government.

(Compiled by Bappa Majumdar and Krittivas Mukherjee; Editing by Alistair Scrutton)

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