Q&A: How significant is Iranian opposition defiance?

TEHRAN (Reuters) - Two defeated contenders in Iran's presidential election denounced the result on Wednesday in clear defiance of Supreme Leader Ayatollah Ali Khamenei, saying Mahmoud Ahmadinejad's next cabinet would be illegitimate.

Moderate former prime minister Mirhossein Mousavi and reformist cleric Mehdi Karoubi unleashed fierce attacks on the outcome of the June 12 vote that returned Ahmadinejad to power.

The election set off the worst unrest seen in Iran since the Islamic Revolution of 1979.

With fresh pressure on the leadership, here are some questions and answers about how significant Wednesday's denunciations are and what they mean for future developments in Iran:

Q: How is the leadership likely to respond to Mousavi and Karoubi calling the future government illegitimate?

A: The clerical leadership is likely to ignore reformers, including Mousavi and Karoubi, and continue to support the new government of hard-liner Ahmadinejad. The opposition has reached a "point of no return" and their statements will be used as an excuse by the authorities to put further pressure on them.

Q: Does this opposition denunciation herald a further crackdown?

A: Political analysts expect a fiercer social and political crackdown in the not too distant future in order to uproot any kind of resistance once and for all.

Q: Is the opposition sufficiently powerful, united and vocal to take on the leadership in this way?

A: The opposition is not sufficiently powerful. Most of its leaders are jailed and their websites and newspapers are closed. They are also not allowed to hold rallies.

Q: How realistic would Mousavi's challenge to election law reform be, how could this take place?

A: It is almost impossible to mount a challenge as hardliners dominate parliament and they have so far been unwilling to reform the election law. There were unsuccessful attempts by moderate former president Mohammad Khatami to reform the law.

Q: What forum is available for the opposition to negotiate with the leadership, or will it take place behind closed doors?

A: To display unity among senior officials in Iran, such talks always take place behind closed doors. It is unlikely that Khamenei will accept any such talks with the opposition. Khamenei has clearly and repeatedly expressed his support for Ahmadinejad and called on the opposition to respect the president.

Q: How sensitive is Iran to possible damage to its reputation internationally and regionally by further quashing of this direct challenge?

A: As the post-election crackdown showed, foreign influence is very limited and especially if the establishment feels threatened internally. On the contrary, it has seized on any Western statement as "interference" in Iranian state matters.

Such statements work against reformists, who in the past called on the West to stop supporting them. In the longer term, the establishment may be more concerned about its image abroad.

Q. Will the opposition statements have an effect on the Assembly of Experts, a clerical body that supervises, appoints and can sack the supreme leader?

A. Very unlikely. Former President Akbar Hashemi Rafsanjani, a Mousavi ally, chairs the Assembly of Experts, which has the constitutional power to depose Khamenei. It has never tried to do so and does not publicly intervene in policy.

Rafsanjani, who had been seen as a possible mediator in the election row, on Sunday praised Khamenei's decision last week to extend a deadline for Iran's top legislative body, the Guardian Council, to examine objections by defeated candidates.

(Editing by Peter Millership and Michael Roddy)