South Sudan's fragile peace deal depends on how Riek Machar, the vice-president, and his erstwhile enemy, President Salva Kiir, can get along and build a framework for the country's future.

The delayed return to Juba of Riek Machar, the one-time and current vice-president, cast a shadow over hopes that the country's humanitarian and economic crises could be on a path to resolution after the signing of peace accords in August 2015.

A rebel and a cause

1953 Born in Leer, in Unity State

1984 PhD in philosophy and strategic planning at Bradford University

2011 First vice-president of newly independent South Sudan

2013 Sacked by President Salva Kiir, who claimed he was planning a coup

2016 Planned to return to Juba after a peace deal was signed

However, Machar's ability to work with President Salva Kiir is in doubt, and South Sudan's route to independence and its short and troubled history as a sovereign state have been shaped by fallings out between Machar and his allies in the Sudan People's Liberation Movement (SPLM).

The distrust between Machar and Kiir was a cause of the civil conflict that erupted after soldiers massacred Nuer people in Juba, the capital, following a skirmish between troops in December 2013.

Machar, a 63-year-old ethnic Nuer, is a divisive figure. To some of his supporters, he is a demigod. Some point to a revered Nuer prophecy as proof he is destined to lead the country. But to opponents, particularly Dinka citizens, Machar is an untrustworthy villain for his role in past violence.

The list of challenges for the new unity government is long: resettling displaced populations, responding to widespread hunger bordering on famine, demobilising troops and seeking peace and reconciliation. Due to the precipitous drop in oil prices and the fighting between the government and Machar's rebels, the administration does not have the resources to address any of these huge needs.

Machar's return should help to raise donor confidence and allow the government to attract more finance from the International Monetary Fund and donor governments. But in the meantime, it is likely that further economic deterioration will lead to a continued rise in crime, and could push militias and generals who are not being paid to loot resources or force some patronage their way.

There are also serious concerns about fighting in Juba, because the government has not been transparent about whether it is demilitarising the city. Nuer who are sheltered in a United Nations base in Juba say they will not go home until they see the city is truly safe and the peace deal is being implemented more fully.

The peace deal has yet to put an end to violence, with fighting – related to a controversial order by Kiir to redraw state lines based on ethnicity – spreading.

Machar amassed a political following when he fell out with Kiir and now faces a choice about what to do with it. Most members of Machar's SPLM-in- Opposition are against the reunification of the SPLM, but Machar supports
the idea of reuniting the party. This has already cost him the loyalty of a few key generals, including Peter Gadet.

Justice, reparations, and reconciliation form a chapter of the peace agreement, but they do not seem to be getting much attention. The African Union is supposed take the lead on establishing a court to try top-level perpetrators, which may include Machar and Kiir. However, with Machar and Kiir maintaining power, the court may not have the latitude to do its work.

In this light, Machar's role as a leader of the 1991 Bor massacre of thousands of Dinka is important. He apologised and was publicly forgiven but he was never punished, and the Bor massacre has been part of the government's anti-Machar rhetoric. Observers reported that Machar's forces again massacred civilians in Bor in 2014.

How Machar and Kiir are able to settle their differences will determine whether peace will return to the state of South Sudan. ●