FACTBOX: What next for Malaysia's Anwar Ibrahim

KUALA LUMPUR (Reuters) - Malaysian opposition leader Anwar Ibrahim was sworn in as an MP on Thursday, returning to parliament after a decade-long absence following what he says were trumped up sodomy and corruption charges.

Here's what Anwar has to do next:

Question: What happens now?

Answer: Anwar's three-party coalition of reformers, Islamists and an ethnic Chinese party have said they will appoint him leader of the 82-strong Pakatan Rakat alliance in parliament. Even so, some political analysts doubt the coalition is durable, largely due to tensions between the Parti Islam se-Malaysia (PAS), which wants an Islamic state, and the Chinese Democratic Action Party.

Question: What steps would he have to take to win power?

Answer: Anwar has to win over at least 30 lawmakers from the ruling coalition to get a simple majority in the 222-seat parliament. He also needs to make sure that he gets enough Malay Muslim MPs to join the opposition alliance as he moves to form a new government by mid-September. Otherwise, leaders from PAS, the Islamist party and a key component of Anwar's opposition alliance, may not be at ease with the partnership, which could lead to the collapse of the loose opposition alliance.

Question: Why September 16?

Answer: Anwar said he plans to bring down the government on September 16 when he wins over enough lawmakers from the ruling coalition.

It was on this date the Malaysian Federation was formed in 1963, bringing together Malaya, Singapore as well as Sabah and Sarawak on Borneo island.

Sabah and Sarawak were strongholds of the ruling coalition until the opposition inflicted heavy losses on the coalition in the March 8 general election.

Political analysts and observers expect that the majority of Anwar's defectors will come from the two East Malaysian states.

Question: What about the pending sodomy case?

Answer: Anwar can still lead the opposition alliance even with the court case going on. Anwar has said he has a strong alibi in the sodomy case. He has given details of his alibi to the police investigating the sodomy allegation.

(Reporting by Soo Ai Peng and David Chance; Editing by Valerie Lee)