If the coalition holds until the 2018 elections, it could lead the strongest challenge yet to Mugabe. But that's a big if.
On 19 April, two of Zimbabwe's most prominent politicians agreed to join forces to unseat President Robert Mugabe. With next year's elections almost in sight, former prime minister Morgan Tsvangirai and former vice-president Joice Mujuru signed an agreement to form an opposition coalition.
They shook hands and smiled at each other before making some comments.
"We have taken the first step to bring all Zimbabweans under one roof so that we can work together to remove the unmitigated repression and misgovernance that pervades our lives", said Tsvangirai.
Mujuru explained: "It took about six months to discuss the coalition. We know your expectations are very high... We are going to deliver a new Zimbabwe."
This alliance has been hailed as a momentous development in the country's politics.
One reason for this is that it brings together two powerful figures that have historically been on opposing sides. As the leader of the main opposition, Tsvangirai has been threatened, arrested and attacked by the government for nearly two decades. Meanwhile, Mujuru, who was a close ally and deputy of Mugabe from 2004 until she was forced out in 2014, was a central figure in the very government authorising that repression. The fact that they have now shaken hands and joined forces is significant.
But Tsvangirai's Movement for Democratic Change (MDC) and Mujuru's National People's Party (NPP) are not the only parties in the coalition. Welshman Ncube's Movement for Democratic Change-Ncube (MDC-N) and Tendai Biti's People's Democratic Party (PDP) have also joined the alliance. Interestingly, Ncube and Biti have a fraught history with the MDC too, both having occupied the position of secretary-general in the party before each falling out with Tsvangirai and going their separate ways.
Outside the party political system, activist groups such as #ThisFlag and #Tajamuka, who led mass protests in recent months, have also formed a coalition to take on Mugabe. These groups are believed to support the opposition coalition, giving it the sense of being not just an association of politicians but broad-based movement.
These developments have understandably caused excitement amongst those who would like to see an end to Mugabe and the ruling ZANU-PF party's 37-year rule. But is the euphoria justified?
Reasons to be optimistic
The opposition has some good reasons to be excited. Mugabe's adversaries have been thwarted time and again, and the spectre of the near win in 2008 still looms large.
In those heavily-disputed elections, Tsvangirai officially garnered 47.9% of the presidential vote, just short of the majority needed to avoid a run-off. Violence against his supporters eventually led him to boycott the second round, leaving Mugabe to retain the presidency. But many suggest that a prior opposition alliance between Tsvangirai and Simba Makoni, who came third with 8.3%, would have been enough to defeat the incumbent outright.
Whether this is true or not is academic. But the formation of the opposition coalition in the run-up to 2018 has certainly generated some momentum. After the MDC's dismal performance in 2013, in which Tsvangirai dropped to 34%, many supporters became disillusioned. But the alliance could rejuvenate hope and morale.
The coming together of the MDC and NPP also combines two differing sets of strengths. For example, the MDC has been effective at mobilising supporters particularly in urban centres and southern parts of the country. But it has always struggled to make inroads in the Mashonaland heartlands from which the ruling party draws much of its support. If Mujuru, who hails from Mashonaland Central, is able to carry over some of the ZANU-PF support base, this pattern could finally change.
However, perhaps the most crucial advantage the former vice-president brings to the opposition is her link to establishment figures in the security sector. These highly influential figures would have a central role in any transfer of power, and some contend that it was Tsvangirai's weakness on this front that prevented him from having a stronger bargaining position in 2008.
By contrast, Mujuru is understood to be close to the chiefs of intelligence services and police, though she reportedly has weaker ties to the army chief. It is even suggested in some circles that her closeness to elements within the security services was one of the reasons she fell out with Mugabe.
Reasons to be cautious
There is thus much for the opposition to cheer, but there should also be considerable caution about the coalition's potential.
Firstly, it is important to note that the grouping hasn't fully coalesced. The leaders of the NPP and MDC have simply signed a memorandum of understanding, which states that at some point in the future, they will contest elections as a united front. There is no formal commitment to an actual coalition just yet.
Secondly, there are still many unanswered questions as to what form the coalition will actually take. For example, will the group field candidates that represent the whole alliance, or will each party still put forwards their own representatives? Moreover, who will lead the movement? The current consensus suggests that Tsvangirai is the favourite, but the talks to determine whether he will be acceptable to all those under the opposition umbrella have not been had.
There are many unresolved issues yet to be decided, and if it turns out that they cannot be resolved, the coalition could fragment as quickly as it came together.
Thirdly, even if the opposition does present a united front in 2018, it will still come up against the ruthless ZANU-PF and its tried and tested election tactics. Without a clear strategy to tackle issues of voter registration and electoral manipulation, the coalition will simply be a boneless mass of motley politicians.
Mujuru's decades-long experience in Mugabe's inner circle means that she is likely to be aware of how elections have been manipulated in the past. Her commitment to the coalition will be tested with the extent to which she is prepared to divulge secrets that may prove useful.
The coming together of opposition parties has unsettled ZANU-PF and its supporters. But the response so far has been rather sedate, mostly confined to dismissing the alliance's prospects and referring to it as a "coalition of failures".
If the grouping holds together up to 2018, however, the resourceful officials in the statehouse and security apparatus will not be short of other more aggressive tactics. In order to derail the opposition, they are likely to try every dirty trick in the book.
Harassing opposition leaders is a well-practised strategy that the state will wheel out once more against Tsvangirai and others. Meanwhile, it may try to undermine Mujuru. In as much as the former vice-president has secrets about the regime, it is inconceivable that the state does not have secrets about her too. Mujuru also faces outstanding allegations of treason, which the government could charge her with in an attempt to derail her campaign.
Alternatively, ZANU-PF could also try to lure back Mujuru back into government. This would not be the first time Mugabe has brought a wayward nemesis back into the fold.
Either way, there is a long way to go until the 2018 elections. If the opposition coalition is able to resolve internal questions and hold together until then, it would represent a momentous development in Zimbabwe's political history. If it maintains the support of civil society, it could lead one of the most broad-based movements against the government ever seen. And if it can use insights from a former insider to come up with effective strategies against ZANU-PF's electoral dominance, it could present the opposition's best chance yet to unseat the ageing President Mugabe.
As of now, however, these are all still very big ifs.