By Syed Shoaib Hasan
BBC News, Islamabad
The announcement that Pakistan's two main opposition parties have agreed to work together will have sent shivers through Pervez Musharraf's camp.
Asif Ali Zardari and Nawaz Sharif are hoping to agree on a coalition
The move could spell the death knell of the president's chances of clinging onto power.
But hope remains for the former military ruler, as the parties are yet to agree on a power sharing formula for the coalition government.
"We have agreed on a common agenda," said former Prime Minister Nawaz Sharif, head of the Pakistan Muslim League - Nawaz (PML-N). "We will work together to form the government in the centre and in the provinces."
He was talking at a joint press conference with Asif Ali Zardari, chairman of the Pakistan People's Party (PPP) and widower of the assassinated former Prime Minister Benazir Bhutto.
"In principle, we have agreed to stay together," said Mr Zardari. "We intend to strengthen Pakistan together."
But Mr Zardari also admitted there was still a lot of ground to cover between the two sides.
Some analysts have taken this as a confirmation that the two have overridden obstacles arising from different national agendas.
Actually though, much remains to be done before the two can actually sit side by side in parliament.
The biggest issue, according to supporters of Mr Sharif, is the restoration of several suspended top judges.
They were removed by Mr Musharraf when he imposed emergency rule last November.
"Mian Sahib (Nawaz Sharif) will never agree to a deal without the judges being part and parcel," a senior PML-N official told the BBC.
"It will cause great damage to our credibility, and go against all the promises we made during our election campaign."
Mr Sharif said: "In principle there is no disagreement on the restoration of the judiciary. We will work out the modalities in the parliament."
Many have taken this as affirmation that the PML-N has agreed to lay aside its key demands on this issue.
"The PML-N wants to share in the power as much as anybody else," contended one analyst.
"This is the one reason they took part in the election, despite the boycott from the other opposition parties."
"They understand that being out of power in Pakistan, is being politically irrelevant."
Others point out that the stakes are much too high for Mr Sharif to be a stickler for what they say are "mere details".
They point to a fact that has been stated time and again by foreign officials - that the West, particularly the US, needs a stable and democratic Pakistan to work as a partner in its "war on terror".
For this, it essential the PPP and the PML-N come together.
It is generally agreed that the legitimacy of any such enterprise will only be established if the major winners in 18 February's elections form the government.
President Musharraf would do better to have his bags packed when we restore the judges
But the international community is also believed to have strongly pushed for Mr Musharraf to stay on as president.
If Mr Zardari is able to convince the PML-N to become part of the future government, Mr Musharraf can consider his position safe - for now.
But if, as some senior PML-N officials have insisted, their party refuses to back down on the justice issue, it may be the PPP which has to give in.
In that case, there would only be one possible outcome.
"President Musharraf would do better to have his bags packed when we restore the judges," said a grinning PML-Q official.
"This is all the notice we are going to give him."