At stake for the AU and the continent was setting a precedent that would allow the AU to intervene in a sovereign country against its will.
For Burundi, what hung in the balance was a concrete mechanism that could restore stability and the rule of law.
This weekend, the unwillingness of African states to set this precedent won the day. In many ways, this is not surprising. Few believed that the Assembly of Heads of State meeting at the 26th AU summit in Addis Ababa would vote in favour of such a bold interventionist strategy and, in the end, the vote was never actually submitted to the heads of state.
What did surprise many was the apparent about-turn that took place among the Peace and Security Council (PSC) member states.
The bold decision from 17 December to deploy AU forces to Burundi was made by the 15-member PSC meeting in Addis Ababa at the level of ambassadors.
According to the PSC communiqué, it was driven, among other things, by information from a mission by members of the AU Commission for Human and People's Rights.
The mission had 'noted violations of human rights and other ongoing abuses, including arbitrary killings and targeted assassinations, arbitrary arrests and detentions, acts of torture, suspension and arbitrary closure of some civil society organizations and media'.
The PSC decision was a response to the sense of urgency about the crisis in Burundi, and the serious domestic and regional impact of the crisis if it escalated.
On Friday 29 January, on the eve of the Assembly of Heads of State meeting at the summit, the PSC met at the level of heads of state and a very different discussion took place.
Some heads of state and members of the PSC, like The Gambia, openly rejected the deployment of a force without consent from the Burundian government.
On the other hand Muhammadu Buhari, the Nigerian president, spoke in favour of sending troops.
The discussion of the PSC at summit level seems to have given significant consideration to the Burundian government's interpretation of the situation.
According to an ambassador from one of the PSC member states, the information that underpinned the December decision to deploy the force 'exaggerated the threat of civil war and genocide.
' The official added that there are far more serious crises across the continent, more deserving of additional peacekeeping capacity, than the situation in Burundi.
This raises a number of serious questions. Is this one-sided view of the situation really shared by other PSC member states and if so, did it drive the backtracking of the PSC heads of state?
Or, is it just a cover for the fact that the PSC heads of state did not want to take a stance against a fellow government, and set a precedent for AU deployment against the will of a sovereign state?
How much high-level support did the force deployment ever have from the presidents of the member states?
Procedurally, the 17 December decision did not need review by another PSC meeting, this time at the heads of state level. It is a standalone decision of the PSC, and ambassadors are mandated by their countries to take decisions.
The next step would have been referral to the assembly, a risky move which was never a given. Does the about-turn signal a fundamental disconnect between ambassadors and heads of state?
Peace and Security Commissioner Smaïl Chergui has taken the lead on the force in the past. But his statement during a press conference at the summit reflected a much more appeasing tone.
Chergui said that the issue was discussed at the assembly and that a decision had been taken to send a high-level delegation - likely at heads-of-state level - to Burundi to discuss the resumption of the East African Community (EAC) talks and the deployment of an AU mission.
If the Burundian government accepts the AU mission, its mandate would be to disarm the various militias, protect civilians in conjunction with the Burundian police, facilitate the work of human rights observers, recuperate illegal weapons and possibly patrol Burundi's borders.
Where does this leave Burundi? Even Chergui acknowledged that the government is hostile toward the AU force. And there is no indication that the AU's softened tone will lead the Burundian government to accept a force deployment.
Burundian Foreign Minister Alain Nyamitwe told journalists at the end of the summit that the government's position had prevailed; adding that the AU delegation was welcome in Burundi, but that a force would not be accepted.
The AU now has very little leverage, and even fewer tools to influence the government, although some believe that it is too soon to declare the AU force dead.
Much emphasis was also placed on a resumption of the EAC-mediated talks. No new date has been set, and the question of who will be represented has yet to be resolved.
Some AU officials have suggested that by taking the threat of the force off the table, African countries hope to coax Burundian President Pierre Nkurunziza back to the negotiating table, where the deployment of a force will be on the agenda.
But, bolstered by the solidarity of African heads of state on the question of the force deployment, will Nkurunziza agree to speak to the political opposition? Or will he balk at the presence of the 'coup leaders' - a catch-all category that his government has applied to many of its political opponents?
There is the further question of the mediation. Behind the scenes, Ugandan President Yoweri Museveni, the EAC-appointed mediator, has been criticised for allowing the talks to lose momentum, and there is a suggestion that another EAC country take over. Agreeing on the mediator, the agenda and the participants will take time.
So will designating the members of the AU's high-level delegation to Burundi. This is one thing that the crisis in Burundi does not have.
On the eve of the summit, Amnesty International published a report indicating the existence of mass graves, which may contain the bodies of those killed in the government crackdown that followed the 11 December attacks.
Critics of the government continue to be targeted, and the killings have not stopped.
If the AU is to maintain momentum, and not look like it is dropping the ball in Burundi, it needs to act fast and concretely.
Stephanie Wolters, Head, Conflict Prevention and Risk Analysis Division, ISS