FACTBOX - No easy options after Musharraf impeachment move

By Zeeshan Haider

(Reuters) - Pakistan's ruling coalition led by the party of slain former prime minister Benazir Bhutto will move to impeach President Pervez Musharraf nearly nine years after he seized power in a military coup.

The plan has heightened fears of instability in a nuclear-armed Muslim nation whose support is seen as crucial to the U.S.-led war on terrorism and NATO attempts to crush a Taliban insurgency in neighbouring Afghanistan

Here are some details of the process and possible political scenarios seen by political analysts and constitutional experts:

CONSTITUTIONAL PROVISIONS

-- Under Pakistan's constitution, half the members of either house of the parliament, National Assembly and Senate can move a resolution seeking removal of the president on grounds he is physically or mentally unfit or to seek his impeachment for violating the constitution or gross misconduct.

-- The Speaker of the National Assembly within three days of the receipt of the notice for removal or impeachment of the president will transmit the notice to the president.

-- The Speaker shall call the two houses of the parliament to meet in a joint sitting after a week but less than two weeks after the Speaker receives the notice.

-- The joint sitting may investigate the charges against the president.