Former Pakistan Prime Minister Nawaz Sharif, like his fellow opposition leader Benazir Bhutto, recently returned to Pakistan from exile to challenge the rule of President Pervez Musharraf. On Saturday he visited Ms Bhutto's grave to pay his respects to the slain leader.
By Lyse Doucet
BBC News, Ghari Khuda Baksh
For years they were the fiercest of political rivals, stopping at nothing to triumph over each other.
But Nawaz Sharif called Benazir Bhutto's assassination "one of the gloomiest days of Pakistan's history".
"It's not just a loss to her Pakistan People's Party. It's a loss for my party, a loss for the whole nation," he said.
Nawaz Sharif joined mourners praying at Ms Bhutto's graveside
As the sun began to set over the Bhuttos' vast mausoleum in the family's ancestral and political heartland, Mr Sharif's convoy roared into the compound in a choking cloud of dust and was immediately enveloped by frenzied crowds.
Any chance of a quiet prayer, by the huge mound of pink rose petals now covering Ms Bhutto's grave inside the cavernous shrine, vanished in a cacophony of shouting, wailing, and chanting.
For a moment, Mr Sharif seemed to be the focus rather than Ms Bhutto in her family's feudal fiefdom.
His emotion was palpable. "We've had a very good rapport over the past four to five years," he told me when I joined him in his vehicle after he emerged from the madding crowds.
He spoke of how she had just called him and sent him a bouquet of flowers for his birthday which happens to fall on Christmas Day. "We had developed a good understanding. We used to consult each other on important national issues."
We sped through a bucolic landscape deep in rural Sindh province in a luxury four-wheel-drive vehicle provided by the Pakistan People's Party (PPP) in a convoy led by a truck bristling with the armed guards he brought with him from his political stronghold to the east, in the Punjab.
But even though bouquets have replaced brickbats, they had both been vying for a third term as prime minister after they ended their years in exile within weeks of each other.
I asked whether elections set for 8 January should still go ahead on time.
"I don't think the conditions are conducive to a free and fair poll, " he said. He accused Mr Musharraf's caretaker government of "putting everything in place to manipulate massively".
Ms Bhutto sent Mr Sharif a bouquet on his birthday on Christmas Day
I pointed out that some senior figures in the PPP were arguing they should compete in the polls because they did not want to be shut out of power. "If we all boycott the elections, President Musharraf wouldn't be able to hold them," he insisted.
He had tried hard to convince Ms Bhutto to boycott the elections when she was alive and then caved in once it was clear he had lost the argument.
Its not certain what other parties, including the ruling faction of the Pakistan Muslim League, will decide now that Pakistan has been plunged into a major political crisis.
Some observers suspect the Pakistan People's Party may want to maximise what could possibly be a massive wave of sympathy following their tragic turn of fate.
Mr Sharif also echoed the anger expressed by many we have met here in rural Sindh - that the government was to blame for Ms Bhutto's shocking assassination.
"President Musharraf's policies are responsible for what's happening," he declared. "It has led to this grave situation in the country."
The government has said there was "every possibility" al-Qaeda was involved, although a prominent Pakistani Taleban leader, Baitullah Mehsud, has denied any responsibility. Mr Sharif said his name, like Ms Bhutto's, was reportedly on an al-Qaeda hit list.
Mr Sharif also met Ms Bhutto's husband
Earlier in the day, at a quieter moment at Ms Bhutto's graveside, some of her closest women friends dismissed the government's account that Ms Bhutto was killed by the blow to her head when she fell back on the sunroof of her car after a gunman opened fire.
"I bathed her at the hospital," Sherry Rehman who is also a leading PPP member angrily explained.
"I saw the bullet wound at the back of her neck, on both sides, where it went through. Her blood was everywhere, on our clothes, and in my car which took her to the hospital."
"She was not just a friend and a party leader," said Ms Rehman. "But she also had a political vision for this country and that has to carry on."
In the midst of the overwhelming grief of Ms Bhutto's allies and friends, urgent political questions are demanding attention: most of all who will lead the PPP; and where does the party go now?
When Mr Sharif went to offer condolences to Ms Bhutto's husband, Asif Ali Zardari, they also discussed politics. "Does he support going to elections?" I asked. "He's a bit uncertain," he replied.
In Pakistan's exceedingly difficult, and dangerous, political landscape, this uncertainty draws together some political friends and foes - if only for this defining moment.