After leading Bhutto's grieving party to a general election victory in February, Zardari played a deft hand to force former president Pervez Musharraf from office in August, nine years after the then army chief came to power in a military coup.

The presidency caps a remarkable transformation for Zardari, who spent 11 years in prison on charges of corruption and murder, although he denied all accusations and was never convicted. He was released on bail in 2004.

Despite Zardari's easy win on Saturday, in a vote involving legislators from parliament and four provincial assemblies, there are fears his rule will mark a new phase of instability in a nuclear-armed Muslim state rife with anti-Western sentiment.

Writing in the Washington Post on Thursday, Zardari, who is 53, said his election would "seal the victory of democracy over dictatorship".

However, doubts over the five-month-old civilian coalition's durability intensified last month after Nawaz Sharif, the prime minister overthrown by Musharraf, pulled his party out due to mistrust of Zardari.

The economy needs billions of dollars of foreign loans to avoid meltdown, while Pakistani Taliban fighters enraged by increasing U.S. attacks from bases in Afghanistan have caused mayhem across the northwest.

The United States has Zardari's commitment to fight terrorism and support NATO's mission in Afghanistan, though ties have been hurt by an American commando raid on a Pakistani border village.

But having pushed Musharraf to return Pakistan to democracy, analysts say, Washington must remain nervous about the outcome.

Pakistan's Kennedys

In the wake of Benazir's slaying, the Pakistan People's Party (PPP) acted in accordance with her political will by anointing Zardari as co-chairman along with their eldest son, Bilawal, a 19-year-old student at Britain's Oxford University.

Yet, Zardari is still seen as an outsider by many old time Bhutto loyalists, having married in 1987 into a family whose tragic saga has made it a Pakistani equivalent of America's Kennedys and India's Gandhis.

He cannot galvanise people in the manner of his charismatic late wife, or her father Zulfikar Ali Bhutto, Pakistan's first popularly elected prime minister, who was overthrown in another military coup and later hanged in 1979. They represented a bridge between the feudal class and the poor and the Westernised elite and the rest.

Benazir once described her acquiescence to a marriage arranged by her mother to the son of a minor land-owning family from the southern province of Sindh as the price she paid "for the political path" her life had taken.

The couple had three children, a boy and two girls.

But estrangement from other branches of her family was another price Benazir paid for her marriage.

Zardari is distrusted by other Bhuttos, having been accused, though never convicted, of involvement in the killing of Benazir's brother Murtaza in Karachi in 1996.

Baggage of the past

On his release in 2004, following an eight-year stretch, Zardari joined Benazir in exile, and the couple were only able to return after Musharraf issued an amnesty to protect them from old cases being revived.

None of the charges, which Zardari says were politically motivated, were ever proven. But the lack of convictions barely helped the reputation of a man often called "Mr. Ten Percent".

"He desperately needs an image makeover," Shafqat Mehmood, a former PPP senator turned political analyst wrote in The News. a Pakistani daily, this week. "Indeed he has to become the exact opposite to what he is perceived to be."

Aides say Zardari had been victim of a "smear campaign" being run by influential sections of the media. Yet there is genuine, though often grudging, admiration for the fortitude Zardari showed during his lengthy incarceration.