Abbas, the wily negotiator, shows his steel

Mahmoud Abbas may be 71 years old and nearing the end of a long political career, but the Palestinian President appears to have suddenly found the fighting spirit of a much younger man.

His live televised call last week for new presidential and parliamentary elections, a direct challenge to the governing Hamas Islamists, was considered a daring move, a serious shaking up of the Palestinian political beehive.

The fallout has been quick. There have been days of battles between Hamas and members of Mr Abbas's Fatah on the streets of Gaza, tit-for-tat kidnappings and the overrunning of Hamas ministries by the President's special guard.

It is the worst internal fighting Palestinians have seen. But through the chaos, Mr Abbas has held his nerve. He stood alongside British Prime Minister Tony Blair in the West Bank city of Ramallah on Monday and promised that he would go ahead with the elections despite the violence.

Whereas over the past nine months, since Hamas came to power in March, he has often wobbled, first issuing an ultimatum and then either not following through on it or paring down his demands, now he looks to be acting with resolve.

While Mr Abbas did leave room for rapproachment with Hamas by saying he still preferred to form a unity government, few expect the Islamists to make the compromises needed for such an administration, first and foremost recognising Israel.

Mr Blair and the Bush administration have both given their wholesale backing to his move although their support comes with a double-edge - it makes Mr Abbas vulnerable to accusations by Hamas and others that he is colluding with the "enemy".

In that sense, his resolve is all the more impressive. Some of Mr Abbas's aides say not even they were certain he was going to go through with the election call. Mr Hamas leaders are also said to have been surprised by the sudden backbone.

Which begs the question, why now?

Aides and those who have known Mr Abbas over his many years in politics say it is the kind of move the wily old negotiator, who helped draft the Oslo peace accords, is inclined to make.

As a leader, they say he is open and a good listener, but when he decides to act, he takes his own counsel and sticks to it. When he is backed into a corner, as he has been by Hamas over the past nine months, he can suddenly become rigid.

"He's patient and hates confrontation, but if he is pushed he can become very forthright, even aggressive," said a journalist who has followed Mr Abbas for 20 years.

"I remember him once saying, 'you take me for a weak person because I am tolerant, but I am not weak'."

It remains to be seen if Mr Abbas will manage to get new elections held. There is doubt over whether as President he has the right to call for them. Officials say that even if they are approved, they may not be held until mid-2007.

It's also uncertain whether Mr Abbas, who has been at the heart of Palestinian politics since Fatah was founded in 1957, will run. He said in January this year that he would not stand for President again when his term ended.

In that respect, perhaps the determination he has shown in the past four days is part of the bravura of someone bringing down the curtain after 50 years in politics, many at the right-hand side of iconic former President, Yasser Arafat.

Those who know him are not so sure. Mr Abbas, a lawyer trained in Egypt who also earned a doctorate in Moscow, is a supreme tactician. He may have a grandfatherly appearance with his thick silver hair, but he has the sharp mind of a younger man.

If he were to step down before elections are held, there would be no natural successor from within Fatah, experts say. The chances are that the movement will rally around, calling on him to stand again. In that way he might manage to coalesce the deeply divided faction just at the crucial time.

It would be a deft move for a septuagenarian.