There are few tangible solutions to Burundi's crisis in sight. But there are some positive actions regional and international actors can take.
The violence in Burundi is evolving and getting worse.
Challenges to President Pierre Nkurunziza's rule are becoming professionalised, as demonstrated by the attacks on two military camps in Bujumbura last December. Godfroid Nyombare - Nkurunziza's former chief of secret service and main plotter of the failed coup last May - has reportedly created an armed rebellion. And security forces have started using rape as a weapon of war, signalling their intent to break Bujumbura's quartiers contestataires psychologically as well as physically.
This evolution is all the more worrying given that there are few tangible solutions to the crisis in sight. As summarised by Samantha Power, the US ambassador to the UN Security Council, Burundi "is going to hell" and there is "no contingency planning, no UN presence, no dialogue".
But what could be done to genuinely improve the situation in Burundi? And by whom?
Give Magufuli a call?
Diplomacy has so far yielded meagre results. The current crisis originated from Nkurunziza's decision to run for a third term and the fact that most of the leaders in the surrounding region are similarly clinging to power does not position them well as potential mediators. Yoweri Musevini, who has been Uganda's president since 1986, has shown little enthusiasm in his role as mediator so far. A diplomatic champion with the stature and skill to broker meaningful talks has yet to be found.
South Africa may seem a natural fit for this role. The country was pivotal in ending the previous civil war in Burundi through Nelson Mandela who was the lead mediator behind the Arusha Agreement. By taking the diplomatic lead on the current crisis, President Jacob Zuma would honour this legacy. However, given the myriad domestic concerns facing the country, Zuma seems unlikely to get involved.
After South Africa, Tanzania might be the next best candidate. The energetic commitment of its new president John Magufuli to reform the country has made him popular in the region, and taking the lead on Burundi would be the perfect opportunity for him to gain standing on the international scene too.
If he did this, he would also be following in the footsteps of Julius Nyerere, who was the facilitator of the Arusha negotiations before Mandela. Furthermore, Tanzania's well-established tradition of presidents stepping down as well as the presence of 140,000 Burundian refugees on its soil would give it the legitimacy to lead diplomatic efforts.
Target sanctions at the right people in the right places
Economic sanctions are likely to be limited in their effectiveness. Nkurunziza is following a short-term logic whereby he intends to crush the opposition while surviving long enough to make his staying in power a fait accompli. Despite the dismal state of the economy, economic sanctions can produce at best mid-term pressure. Furthermore, they are likely to hurt the population before the ruling elite.
The best way economic sanctions could work, however, would be if they targeted the leaders of the repression - i.e. the top brass of the Burundian security apparatus. Currently, Nkurunziza reigns but does not govern.
Afraid for his security, he is hardly in Bujumbura as his recent meeting with delegates of the UN Security Council in the town of Gitega rather than the capital testifies. The day-to-day repression is therefore organised by the military and party big men in Bujumbura.
Some of these figures have already been sanctioned, but only timidly and ineffectively. The EU and US have banned certain leaders from travelling to their territories and frozen their assets.
However, while this may have symbolic significance, it does little to change matters on the ground. These men do not have strong links with the US or Europe and their respective banks. Instead, their money is in Kenyan or South African banks and for sanctions to be effective, they should target regional visas and assets.
Leverage Burundi's own peacekeepers
On 17 December, the African Union (AU) approved the deployment of a 5,000 peacekeepers to Burundi. The government responded by saying it would see it as an invasion and that Burundian forces would fight such a force.
Intervening against the wishes of the host country would be a first for the AU and the willingness for the regional leaders to set such precedent is unclear. Furthermore, an operation of this size would probably be too small to protect the population outside Bujumbura.
An AU intervention in the military sphere could however take another form. Threatening to remove Burundian troops from the African Union Mission in Somalia (AMISOM) could be an effective way to twist the arm of the Burundian government.
In a context of shrinking resources and rampant divisions in the army, AMISOM's generous wages go a long way in stabilising the Burundian military. Threatening to suppress this source of revenue is unlikely to fall on deaf ears.
Keep a close eye on Rwanda
Recent allegations that Rwanda is recruiting and training Burundian refugees to fight in Burundi are alarming. If true, they could signal danger for both Burundi and Rwanda itself.
After all, a Rwanda-sponsored rebel movement would give the Burundian government the perfect opportunity to portray opposition as the lackeys of a Tutsi-led Rwanda. For Burundian politicians who have occasionally resorted to ethnic discourse since the beginning of the crisis, such a confirmation would be a blessing.
In the longer term, questions also arise over what would happen if a Kigali-backed rebel group actually fought its way to Bujumbura. If the Burundian government were overthrown, this group would not be the only rebels in town and in a contest for power, being able to paint the Rwandan-backed rebels as puppets of the "Rwandan Tutsi" would be a tempting strategy for any competing armed group looking to foster popular support.
It makes sense for Rwanda to want to be proactive regarding Burundi. The country's leadership derives its legitimacy from having stopped a genocide in 1994.
There are more than 70,000 Burundian refugees on its soil. And members of the ruling elite in Kigali have family connections in Bujumbura. Nonetheless, clandestine support from Kigali to an armed group risks further jeopardising the stability of the region. If Rwanda wants to intervene, it would be in its own interest to do so through a multilateral approach.
Get independent radio stations back on air
The re-opening of independent radio stations would probably be the most important, immediately tangible and easily-defined objective of any initial negotiations with Nkurunziza. Independent radio shows are the best way to debunk ethnic discourse and wild rumours.
A free media would also ensure a better knowledge of what is happening outside Bujumbura. Given the media blackout in the country, if mass killings were to happen in the countryside, it would be hard for the world to know.
The Burundian government is playing for time and has few reservations in using violence as it tries to keep hold of power. There are no easy or quick solutions, and external actors may only have a limited scope to help resolve the escalating situation.
Nevertheless, they cannot ignore any leverage they may have and, while partial and limited, some of the above suggestions could make a positive difference and open up productive avenues for engagement in resolving Burundi's deepening crisis.
Benjamin Chemouni is a PhD candidate in the Department of International Development of the London School of Economics and Political Science (LSE). His research focuses on Rwanda and Burundi. Follow him on twitter at @BChemouni.