Mr Marulanda has seen presidents come and go

More than 40 years, ago Mr Marulanda headed a band of some 20 guerrillas, dodging military patrols and living furtively in the jungle.

Now he leads the 17,000-strong Revolutionary Armed Forces of Colombia (FARC), and it is the military that - more often than not - seek to avoid him.

Not bad for a man who had the most rudimentary of education and has never lived in a city.

President's weak hand

On Thursday, President Pastrana goes down to the 42,000-square-kilometre Farc safe haven to try to persuade Mr Marulanda to restart stalled peace talks.

As usual, the wily 70-year-old guerrilla leader is holding all the cards.

The bottom line is that Mr Pastrana has staked his presidency on finding a negotiated solution to Colombia's civil conflict and has a year-and-a-half left of his administration to show some results.

Mr Pastrana's course has been unpopular

Mr Marulanda, as head of the FARC, has seen 10 presidents come and go and he will only proceed at his own pace and on his own terms.

But President Pastrana is under increasing pressure from a disillusioned Colombian public to get tough with the FARC.

They are tired of repeated concessions to the guerrillas, who have only replied with record levels of kidnapping, violence and instability.

No aces

But President Pastrana has no ace up his sleeve, no way to really put pressure on the guerrillas.

The FARC has little to fear from the army

His army, even boosted by the lion's share of $1.3 billion of US military aid, has no chance of defeating the FARC militarily.

But nor is the FARC able to fulfil its stated aim of seizing power.

So the best President Pastrana can hope for on Thursday is that Mr Marulanda will agree to resume talks.

But the rebel leader is expected to charge a high price: a renewal of the safe haven until the end of the Pastrana administration, a prisoner exchange and more promises from the government to fight the right-wing paramilitaries that have been killing suspected guerillas.