The role played by the security forces will be important, since they have been a bulwark of ZANU-PF rule.
Military leaders have at times publicly denounced opposition politicians, saying they would not allow such people to take power, even if elected.
Zimbabwean civil society is active and brave in defending human rights and the rule of law, but faces an entrenched bureaucracy, partisan state-owned media, and the hardline security establishment; all these are hostile to robust democracy.
That leaves the international community.
The neighbouring countries, especially South Africa, will not intervene unless asked by Zimbabwe, or unless a full-blown crisis erupts, as one did in 2008-09.
Having learned from their hubris and incompetence in Iraq and Libya, the Western powers’ taste for regime change is much reduced.
Those Western powers have also lost interest in Zimbabwe over the last decade, distracted by challenges in the Middle East and at home.
Their fierce denunciations of Zimbabwe’s 2000-03 land reform are now a distant memory.
The Western power with the deepest connection to Zimbabwe, the United Kingdom, is absorbed with the self-inflicted wound of Brexit and has little time for its former colony.
As for the United Nations, the Security Council is overwhelmed and divided by other conflicts.
In short, a serious breakdown of political and civil order in Zimbabwe is likely, along with attendant human rights abuses and even a humanitarian crisis.
It is coming soon, as friends and foes alike realize that Robert Mugabe cannot last forever.
Zimbabwean politicians are not the only ones who need to plan for his departure.
The question is, who in the international community will step up and lead an effort to prevent or mitigate the impending meltdown in Zimbabwe, or even to plan for dealing with the fallout?
By Lauchlan T. Munro and John Packer. This article was first published by the Ottawa Citizen