By Syed Shoaib Hasan
BBC News, Islamabad
Former Pakistani Prime Minster Nawaz Sharif has returned to Pakistan after eight years in exile.
Mr Sharif is popular in the Punjab province
He left the country in 1999 after current President Pervez Musharraf toppled him in a coup.
It is believed that Gen Musharraf is hoping that Mr Sharif will be able to dent Benazir Bhutto's prospects in the forthcoming parliamentary elections.
When Mr Sharif attempted to return in September, Gen Musharraf was at that time facing the biggest political challenge of his eight years in power.
Pakistan had been engulfed in months of political turmoil triggered by Gen Musharraf's crude attempt to sack the chief justice of the Supreme Court.
At the same time, Islamist militants were engaged in continual attacks on the military.
The government's response to Mr Sharif's return was unequivocal.
Soon after his arrival he was bundled onto another plane and sent back to Saudi Arabia.
The government was adamant that if he had stayed in Pakistan he would have been locked up.
This time the government downplayed his homecoming to Lahore. There was a big security presence, but no heavy-handed tactics against the Sharif supporters who welcomed him home
The lack of mud-slinging from Mr Sharif and Gen Musharraf's advisers may seem surprising. So what's going on?
For veteran political observers it is just another example of Pakistan's flip-flop politics.
"The problems started when she landed in Karachi", says one analyst - "she" of course, being Benazir Bhutto, the "other" former prime minister, who flew home in October after nearly eight years of self-imposed exile.
It is estimated that nearly half a million people came out to greet Ms Bhutto, the leader of Pakistan's largest political party, the PPP.
The huge turnout stunned Gen Musharraf and his advisers.
Ms Bhutto's return was all part of an agonised political deal with Gen Musharraf.
Ms Bhutto's deal with Gen Musharraf has unravelled
Even though the two dislike each other intensely, Ms Bhutto agreed to support Gen Musharraf's bid for another term as president - in return for being allowed to become prime minister for a third time.
The United States and the UK were supportive of the scheme.
Western diplomats were getting more and more worried at Gen Musharraf's growing unpopularity and his failure to take on the rampaging pro-Taleban militants.
The hope was that a genuinely popular democratic government led by Ms Bhutto would be far more effective in taking on the militants.
If Mr Sharif had been allowed to return before that, it could have disrupted Ms Bhutto and Gen Musharraf's plans.
Thus the silence from Ms Bhutto when her fellow democratic politician was deported by a military leader did not surprise many here.
But the grand political deal soon began to unravel, and the mistrust between Ms Bhutto and Gen Musharraf became increasingly visible.
Gen Musharraf continued to make clear that he was being forced into allowing "corrupt leaders" back into Pakistan.
Ms Bhutto repeatedly said she was only talking to a military dictator for the sake of democracy.
The cracks appeared sooner than most expected, and the mass turnout for Ms Bhutto's homecoming was what destabilised the deal.
President Musharraf's team knew that Ms Bhutto would always be strong in Sindh province, of which Karachi is the capital.
But they were alarmed at how many people had travelled from Punjab province to greet her.
Could it be that she would do far, far better in the promised parliamentary elections than they had anticipated, thus making her too powerful a figure?
Gen Musharraf's imposition of emergency rule on 3 November aggravated relations with Ms Bhutto's supporters and senior PPP leaders began to clamour for a complete break with the general.
Things finally came to a head when Ms Bhutto was put under house arrest to stop her leading any more mass public rallies.
All possibilities of a deal with President Musharraf "are now finished", she told reporters.
Thinking the unthinkable
The pressure was on Gen Musharraf again, not least because of the international condemnation of emergency rule and criticism from his ally, President George Bush.
The governing PML-Q now looks increasingly likely to fare badly in the January elections
So, once again in Pakistan, the unthinkable has begun to look like the palatable.
A few days ago Gen Musharraf flew to Saudi Arabia for a quick meeting with the country's monarch.
Four days later, the Sharifs announced they would be coming back to Pakistan - another deal had been done.
Has the General made a new deal with a different former PM?
Many observers believe Gen Musharraf is only allowing Mr Sharif to return home because he is the one political figure who can prevent Ms Bhutto succeeding in Punjab province.
Whoever wins the Punjab wins the election.
The best outcome for Gen Musharraf would appear to be a divided electorate, resulting in no one party dominating parliament.
"That is the only thing that can keep General Pervez Musharraf relevant any more," is how one analyst put it.
"But, even then, there are no guarantees, after all this is Pakistan."