One argument in favor of the Obama administration's decision to arm the Syrian rebels is that the move will help create incentives for the Syrian government to negotiate a deal at a planned peace conference in Geneva. It's no secret that the balance of power in the past few weeks has shifted in favor of the Syrian regime, particularly after the regime regained control of the strategic town of Qusair. If the betting before was that time worked against President Bashar Assad, the military equation on the ground dramatically shifted the betting. It is thus assumed that with rebels strengthened, Mr. Assad will have more incentives to reach a deal and end the conflict. This logic is flawed. Evidence from hundreds of cases of civil conflict since the end of the Cold War indicates that the outcome is more often the opposite: supporting rebels only extends the conflict and reduces the incentives of government to reach a deal.
Why would providing external support to the rebels make it more difficult to reach a peaceful settlement? There are a few reasons. Research in political science has shown that intervention that creates a balance of power between rebels and the government can prolong wars. In our own work studying civil wars, we have carefully examined data from 218 of cases extending from 1990 to 2011 and covering wide geographic regions including the Middle East. We find that conflicts in which the rebel group received external support from a third party lasted significantly longer than civil wars that did not involve external support.
Moreover, rebel groups that receive arms are less likely to reach cease fire agreements that move the dispute toward resolution. The intent of arming the rebels is to enable them to defend themselves and negotiate a peace agreement with the government. However, surprisingly, giving external support to rebels may also make the government less likely to offer the rebels a peace settlement. This happens because the government usually knows that the external support increases the ability of rebels to bear the costs of war. This allows the rebels to hold out for a better settlement and creates an incentive for rebels to renege if they do make a deal. Because of this, a government often prefers to continue fighting the rebels instead of negotiating with them. For example, in the Angolan civil war with the National Union for the Total Independence of Angola (UNITA), the government refused to negotiate with the rebels until external support to the rebels was stopped.
At first glance, it may appear that the "right" thing to do is provide arms to the rebels. The logic behind the argument for arming the rebels is that by providing them with arms they can defend themselves against the Syrian government, a government that has recently been confirmed to have used chemical weapons against the opposition. Part of the reason that opinions differ on supporting rebels is how that support is perceived. The Assad government certainly does not expect the rebels to use their new arms defensively. Rather, the arms will make the rebels more threatening. Yet, policy makers in the United States and Europe who support arming the rebels make the argument in terms of providing the rebels with a means of self-defense, or of providing balancing leverage in the negotiations.
There may be other reasons for arming the rebels, including denying Mr. Assad a military victory and showing global determination as Mr. Assad continues to receive support from his key allies, especially Russia, Iran and Hezbollah. But if the aim is primarily humanitarian, such as reducing the number of civilian casualties, or improving the prospects of a political settlement, this move is unlikely to achieve its objectives. Although it appears only humane to provide the rebels in Syria with arms, if this civil war follows the general pattern seen in the data, the civil war in Syria may turn out to last longer with greater loss of life because of the external support being provided to the rebels. At the very least, we should be aware that supporting rebels can have unintended consequences for the chance of conflict resolution.
Kathleen Gallagher Cunningham (email@example.com) is an assistant professor in the University of Maryland's Department of Government and Politics. William Reed (firstname.lastname@example.org) is an associate professor in the department.