By Mohamed A. El-Erian

For two months now, developments in the Middle East and North Africa (MENA) have taken most by surprise. What started as an isolated protest in Tunisia has developed into a regional phenomenon that has toppled some regimes and is threatening others. Indeed, every day seems to bring yet another new dimension to an historical event that is changing the region and impacting the global economy.

Governments across the globe have spent weeks playing catch up in the midst of previously unthinkable developments in MENA. They have organized emergency evacuations of citizens and constantly responded to new realities on the ground, including the brutal violence in Libya.

Understandably, many are wondering about what comes next; and, understandably, predictions are subject to unusually wide bands of errors and uncertainties. With this said, I suspect that we may now be entering a period of much greater differentiation among MENA countries.

If this is correct, the sense of an unstoppable and unpredictable tsunami of change may be replaced by a need to distinguish among different country dynamics. And should this materialize, the world will face a dual challenge — understanding and dealing with what may well be four distinct groups of countries within MENA; and comprehending a new set of regional dynamics which involves different interactions among countries. Let us address each in turn.

Post-regime change countries, such as Egypt and Tunisia, are working hard to complete their revolutions and to ensure an orderly and complete transition to greater democracy and individual freedoms. Success lies in the following factors: defining a vision and associated action plan which command sufficient popular support; coordinating simultaneous progress on related economic, political and social issues; and implementing appropriate mid-course corrections as needed.

This is a doable but difficult task that must be undertaken primarily by domestic institutions (though each county will also need the timely support of friends and allies). It will not be done overnight; it will not be linear; and it requires a number of prerequisites, including the urgent and orderly resumption of normal daily economic and financial life.

Some other countries in the region (possibly Bahrain) could well join Egypt and Tunisia in experiencing some type of relatively peaceful regime change. Governments in these countries are already on their way to recognizing that basic change is unavoidable to accommodate the widespread demands of their people.

A third group of countries, including in the GCC, will likely avoid regime change. Governments have the willingness and ability to respond proactively and preemptively. They start with greater political and social legitimacy, as well as better means to help citizens deal with economic and social pressures. Indeed, some have already shown considerable skillfulness in understanding the dynamics in play and have reacted accordingly.

The final set consists of countries, including Yemen, is in the process of overthrowing their repressive governments but also risk becoming “failed states.” If they are not careful, fragmentation and chaos could result, with the risk of inflicting tremendous further pain on citizens and also threaten to undermine the stability of other countries.

It is imperative to recognize and understand the dynamics of each of these four groups, and to respond accordingly. It is also important to appreciate that the dynamics of the region as a whole will change, adding another element of complexity.

This is particularly relevant for institutions whose mandate is to promote regional integration, such as the Arab League. But the implications go far beyond.

Already, we are seeing massive movements of migrant labor within the region. Just witness the heart-wrenching scenes at Libya’s borders with Egypt and Tunisia. This adds to the challenges facing the region, as well as increases to the risk of illegal migration to Europe and elsewhere.

After years of under-achievements, MENA is in the midst of historic change that has caught much of the world both unprepared in analysis and slow in response. As the international system plays catch up, broad generalization about the region (and the initial sense of unpredictability) should give way to greater understanding and differentiation.

Getting this right is essential if governments, both within and outside the region, are to assist in constructively channeling the unleashed energy of MENA’s citizens who have courageously taken to the streets in order to improve their wellbeing, and that of future generations.

Mohamed El-Erian is the CEO of PIMCO. He spent part of his childhood in Egypt where his father was a professor of international law at Cairo University and then served as an Egyptian diplomat and was elected to the International Court of Justice in 1978. The opinions expressed are his own.