ISLAMABAD: Calm has returned to Pakistan's beautiful Swat valley, a battle ground for two years as the government fought militant commander Mullah Fazlullah's reign of terror.

Since the government accepted a controversial peace deal earlier this month shops have reopened, the displaced have come home, relief supplies have arrived, and boys — and even some girls — are back at school.

However, the success of the decision to allow sharia law as the only justice system in Swat depends on key elements — including how it will be implemented and who will be responsible for enforcing it — none of which is any clearer 10 days after the ink dried.

Pakistani Foreign Minister Shah Mehmood Qureshi, in Washington to contribute to a US review on the 'war on terror,' called the deal a 'quick dispensation of justice' and 'not any appeasement towards militants.'

But how will justice be dispensed and who will be responsible for enforcing it: the Taliban or the government? In any case, under Pakistan's constitution, no law may violate the Holy Quran or the sharia law throughout the country — so how will things be different in Swat?

Negotiations are continuing between the authorities and the pro-Taliban cleric who signed the deal, Fazlullah's father-in-law, Sufi Mohammad, but nothing has been announced to quash speculation that the deal is flawed.

The west has sounded alarm bells, worried that the draconian version of sharia law imposed in Afghanistan after the Taliban came to power in 1996 will be replicated in Swat, just 100 miles from Pakistan's capital.

Others rule out any prospect of 'Talibanisation,' saying Swat will instead return to the benign system of justice it enjoyed as an independent state before 1969, with pared down courts and verdicts speeded up.

'The new system of justice, if implemented will only lead to the formation of courts that existed in the area before,' said retired Supreme Court judge Wajihuddin Ahmad.

'The law has nothing to do with the issue of growing beards or the education of girls in the region. The people of Swat want issues to be tackled in their own courts...we should allow them the kind of courts they want,' he added.

Such a scenario could play well into the hands of the government, which says it is ill-equipped to fight a prolonged insurgency in Swat as well as across semi-autonomous tribal areas on the Afghan border.

But Pakistan's secular elite has rubbished the idea that 'technical' concessions will satisfy Fazlullah, warning that without serious safeguards, the deal will effectively cede Swat to the Taliban.

After the Swat deal, US Senator John Kerry warned of apocalyptic dangers now facing Pakistan, calling for up to five billion dollars in urgent aid to avert chaos in the country.

'If we fail, we face a truly frightening prospect: terrorist sanctuary, economic meltdown, and spiraling radicalism, all in a nation with 170 million inhabitants and a full arsenal of nuclear weapons,' Kerry said.

Analysts warn the authorities must move quickly in Swat to make the deal work. Police and security must take back control where the militants disband checkpoints, militants must disarm and illegal militias banned.

Damaged schools, public property and homes must be rebuilt, more judges and court officers recruited, organised militias brought to trial and the militants prevented from exercising any extreme interpretation of sharia law.

'We cannot be sure whether the deal will succeed because of the obvious operational problems that may occur at a later stage in its implementation,' political analyst Hasan Askari told AFP.

However, the rapid collapse of past peace agreements between Pakistan and militants in the semi-autonomous tribal areas, where US missile strikes have been targeting suspected al-Qaeda militants, bode ill for its chances.