(CNN) -- A second round of talks between two disputed governments of Honduras is scheduled to take place Saturday in Costa Rica
Deposed Honduran President Jose Manuel Zelaya says he must be returned to power.
The outcome of this weekend's talks, following an unproductive initial mediation last week, could set the tone for how the crisis, now in its third week, will play out, observers say.
"If you take too long to resolve this type of issue, the force of the mediation loses clout," Larry Birns, director of the Council on Hemispheric Affairs, said.
Deposed Honduran President Jose Manuel Zelaya was ousted in a military-led coup June 28. Despite international condemnation for the coup, the interim government of Roberto Micheletti, who was named interim president by Congress after Zelaya's ouster, has remained steadfast.
Neither Micheletti nor Zelaya will personally take part in the talks at the home of Costa Rican President Oscar Arias, choosing instead to send high-level delegations.
But in remarks this week, both have made their positions clear.
Zelaya issued an ultimatum demanding his restoration as president, as resolutions by the Organization of American States and United Nations have stated. If this weekend's negotiations don't land him back at the presidential palace, he will consider the talks a failure, Zelaya said.
For his part, Micheletti said he would be willing to resign, but only on the condition that Zelaya not come back to power. Micheletti and his supporters, both in and outside of Honduras, argue that the military action was not a coup, but a constitutionally legal transfer of power.
The two sides had reached some agreements, including the creation of a unity government that would include all political parties and amnesty for crimes committed on both sides, Arias told the New York Times in Thursday's edition.
But the key polarizing issue -- Zelaya's political fate -- appears to be the biggest hurdle to a resolution.
Even though Micheletti's interim government has found itself diplomatically isolated, the pressure may actually be on Zelaya this weekend.
Immediately after his ousting and exile, Zelaya, who narrowly won the presidency in 2005, became a figure that many Hondurans rallied around.
"All of this that has taken place has enlarged his constituency," Birns said.
Nonetheless, time is not on Zelaya's side.
For one, Zelaya's term is up in six months. And as normalcy slowly returns to Honduras and a resolution evades the ousted president, "you become a dead fish, and every day that passes, you stink more," Birns said.
Zelaya unsuccessfully tried to return to his homeland once already, an event that triggered clashes between his supporters and police.
Any non-negotiated return could result in similar unrest.
The fact is that even though Zelaya has the backing of the international community, he is dependent on Micheletti to let him back into his country, said Christopher Sabatini, senior director of policy at the Americas Society and Council of the Americas.
"As illegal as his ouster may have been, there has to be some pressure on him to accept some compromise," Sabatini said.
For example, Zelaya could admit that he violated his constitutional mandate, Sabatini said.
Before June 28, Zelaya had been at odds with Honduran lawmakers, the supreme court and the military over a referendum he had planned to hold. Congress had forbidden it, and the supreme court ruled it illegal.
Hondurans who supported the ouster thought Zelaya was trying to maneuver a way to seek re-election in November, an assertion he has denied.