One approach in trying to deal with the violent internal conflicts that have gripped countries like Iraq and the Ukraine is the idea of power sharing between the regimes and those challenging them. The former Russian-backed president of the Ukraine tried it — unsuccessfully — in January. And, in Iraq, the U.S. and its allies have pressed the Shiite-dominated government to pursue such a strategy by bringing more Sunni factions into the fold in hopes of defusing challenges from Sunni militants.

A new study, published in the journal of Conflict Management and Peace Science, looked at power-sharing agreements negotiated after civil conflicts and found that they have a mixed record.

For example, the war in Afghanistan arose in part out of a failed power-sharing agreement in the 1990s that involved both political and military concessions to rebel groups. After the Soviets abandoned their invasion of Afghanistan in 1989, various militia groups fought for control of the country. An agreement was reached in 1993 establishing a government, although it quickly fell apart, setting the stage for the Taliban’s control over the country.

The CMPS study examined different types of power sharing between 1989 and 2006, including political (gaining seats in the parliament or government), military (rebel groups becoming part of the military or police forces), economic (becoming part of state-owned businesses or government bodies overseeing the economy) and territorial.

Out of the 111 power-sharing agreements that were reached during the period under study, conflict resumed between the government and the associated rebel group in 55 of them (50%). The vast majority of power-sharing agreements took place in Africa, but the highest rate of conflict resumption was in Asia, with 71% of conflicts reigniting, which the study cites as an example of how difficult it can be to resolve civil conflicts. Other scholars have noted how hard it is for combatants to make credible commitments that they will follow through on promises to address the causes of the conflict.

In 1997, for example, the government of Tajikistan signed a peace agreement that shared political power with the United Tajik Opposition, which it had been contending with during several years of fighting. The agreement quickly fell apart, however, with one UTO faction rejecting the agreement and resuming fighting.

All the power-sharing agreements studied by the researchers occurred before 2006, and many were in Africa and Asia, so the findings — concerning both the rate of success and the most effective types of agreements — are not necessarily applicable to more recent conflicts, such as those happening in Iraq, Syria or Ukraine.

In Europe and the Americas, meanwhile, all power-sharing agreements (nine and five, respectively) held. The most famous example where an agreement based on power sharing was successful is the Dayton Agreement, which resolved the conflict over the breakup of former Yugoslavia and set up a system of territorial and political power sharing among ethno-religious groups in Bosnia-Herzegovina. While there have been occasional tensions since, full-scale fighting has not broken out again.