The future of U.S. military support for Bahrain, starting with a $53 million (33 million pounds) arms deal now on the line, hinges on the findings of a human rights investigation into the Gulf kingdom's handling of popular protests earlier this year.

The jury is out.

Originally due last month, the report was pushed back to November 23 after Bahrain's longtime superpower ally said it would reassess weapons sales once it had seen the result of the inquiry, a move analysts say has given it more political clout.

Not only could the report help decide whether Bahrain gets arms that human rights activists fear could be used to crush further dissent, it could also dictate whether Bahrain heads for more communal violence or towards political reconciliation.

There will be almost certainly some behind-the-scenes wrangling before the final report is released because there is more at stake than was originally assumed, said Shadi Hamid, director of research at the Brookings Doha Centre in Qatar.

The U.S. Congress is paying more attention and the arms deal is being called into question. So there is quite a bit at stake for the Bahraini government and the report is going to get a lot of attention, for better or worse.

Bahrain's Sunni Muslim rulers quashed a pro-democracy street movement in March with the help of martial law and troops called in from Saudi Arabia and the United Arab Emirates. They accused the protesters, who were largely from the island state's majority Shi'ite Muslim population, of sectarian motives.

Bahrain says it needs the military hardware, including armoured Humvee vehicles and missiles, to defend itself from non-Arab Shi'ite giant Iran, which it accuses of fomenting the revolt to turn Bahrain into an Islamic republic. Iran denies it.

A White House spokesman said the weapons would be strictly for Bahrain's external defence. Rulers across the Middle East this year have justified crackdowns on protesting civilians by blaming the unrest on foreign conspirators.

The arms sale became unusually controversial in Congress because, critics say, it highlighted a double standard in U.S. policy towards popular Arab uprisings.

Whereas the Obama administration called on beleaguered autocratic leaders in Egypt, Tunisia, Libya, Syria and Yemen to step down, it has done little but chide Bahrain, which has hosted U.S. naval headquarters in the Gulf for more than 60 years and is at the front line of efforts to contain Iran.

ANSWERING CRITICISM

Bahrain's rulers invited the fact-finding mission by human rights lawyers in response to international criticism of its crackdown on the demonstrations, during which at least 30 people were killed, hundreds wounded and more than 1,000 detained.

Police and protesters still clash almost daily in Shi'ite villages ringing the capital Manama.

The commission, which is paid for by the Bahraini government, said the delay in publishing results arose from the sheer volume of testimony given and because some ministries and government agencies had yet to respond to its inquiries.

While analysts agree it was probably overwhelmed, some say the Bahraini authorities may have sought to hold up the report by not meeting the panel's requests on time.

Direct pressure is going to be limited because I think they can't really threaten the commission, said Jane Kinninmont, analyst at the UK-based think-tank Chatham House.

They may be able to influence them and to try to encourage them to think that certain things may be more or less in the country's interest. And of course there is the question of how much access they've allowed the commission, she said.

The panel has been plagued with controversy from the start.

Its head, Cherif Bassiouni, said in August he did not believe torture had been a systematic policy, a gaffe that threatened to discredit the commission among many Shi'ites, who stormed its offices in anger.

After that, Bassiouni said he would not speak to the media, but he gave an interview to an Egyptian newspaper this month in which he backtracked, saying torture had been systematic, if limited, citing 300 documented cases.

Bahraini authorities have conceded there were isolated cases of human rights abuses, but denies there was ever a policy to use excessive force against protesters and detainees.

We hope that the report will be an opportunity for real reform and reconciliation between the people and the ruling family, said Mattar Mattar, a former member of Bahrain's largest Shi'ite opposition bloc, al-Wefaq. Currently the regime is on the wrong track when they think that they can solve problems by denial, ignorance and procrastination.

CHANCE FOR RECONCILIATION?

Until the report is out, Bahrain is holding its breath.

If the commission report shows that the government seeks to prevent demonstrations at all costs, then the (arms) sale is likely to be derailed, said Kenneth Katzman, a Middle East expert at the nonpartisan U.S. Congressional Research Service.

If the commission's report shows that Bahrain's leadership has tried to address international criticism and concerns about how it has suppressed the demonstrations, then I think the sale is likely to proceed eventually, he said.

Even if the transaction goes ahead, the tying of the deal to the human rights report gives the U.S. leverage that could be used to push for reforms in Bahrain after the investigation is wound up, analysts say.

I think the U.S. role has been to strengthen the reformers by using a kind of pressure that the guys in the security establishment have to be affected by because it directly affects their supplies of arms, Kinninmont said.

Bahrain has said it will hold accountable those the commission implicates in any maltreatment.

At best, analysts say, the report could be a springboard for reform, unifying wildly divergent accounts of events to provide the basis for a way out of a political quagmire that threatens Bahrain's reputation as a business-friendly banking hub.

At worst, the opposition fears, once the commission has left and Bahrain is sure of getting its U.S. weaponry, there could be a renewed crackdown on public dissent.

There is so much at stake and people are pretty dug in on both sides, said a senior State Department official who declined to be identified. But I think the report offers probably a unique opportunity for a re-examination of all of those things and offers the potential to break out of what has really been an impasse for the past six months.

Some in the opposition doubt the report will address grievances underlying the discontent that sent thousands onto the street earlier this year, or prevent it from erupting anew.

There will be many temptations offered with this settlement, from releasing prisoners, returning those expelled (from Bahrain) for their actions, withdrawing the security from the street, the 14th February Youth opposition group said in a post on the Bahrain Online forum.

But there will be no strategic solution to the issue to prevent the recurrence of these problems...

(Additional reporting by Andrew Quinn and Jim Wolf in Washington; Editing by Andrew Hammond and Mark Heinrich)