A report issued by the U.S. Department of State last week cites a sharp decline in the number of worldwide terrorist incidents from 11,641 in 2010 to 10,283 in 2011.

The 12 percent drop in the number of terrorist attacks to the lowest number of incidents since 2005 is good news for U.S. counter-terrorism officials. It's even better news for U.S. President Barack Obama as he seeks to contrast the impact of his foreign policy decisions with those proposed by his Republican rival, former Massachusetts Gov. Mitt Romney.

But the recent decline in terrorist incidents isn't surprising based on my own terrorism research.

The State Department's politicized claim that the targeted takedown of Osama bin Laden "puts the (al-Qaida) network on a path of decline that will be difficult to reverse" is difficult to substantiate but they may be correct that the worldwide decline in terrorist incidents is a function of bin Laden's removal.

My own analyses of terrorist incident data suggest that the loss of a key leader may have a demoralizing effect that impacts the frequency, dispersion and lethality of subsequent terrorist activity.

In fact, the decline in incidents after the killing of bin Laden in May 2011 is consistent with the decline in transnational terrorist incidents that occurred after Iraqi dictator Saddam Hussein was captured in December 2003.

My own research indicated a pattern of transnational terrorist incidents declining after the breakup of the U.S.S.R. in the early 1990s but rising, with some dips, by as much as 74 percent after the onset of the War on Terrorism in late 2001.

The invasion of Iraq in mid 2003 was also associated with an increase over and above the period before the invasion (in this case 26 percent).

However, the capture of Saddam in December 2003 was associated with a 77 percent decrease in transnational terrorist incidents and a 22 percent decrease in deadly incidents compared to the 10-year period before the capture.

In raw numbers, Saddam's removal reduced the number of incidents by about 75 attacks in the next 12-week period. Saddam's capture was also associated with a 50 percent decrease in the number of countries with transnational terrorist incidents and an 89 percent decrease in the number of American victims.

Unfortunately, the effects lasted only so long and, at least in the case of Saddam, were undone by the release of photos depicting torture at Abu Ghraib.

The conventional wisdom suggests that governments have several tools at their disposal to manage the problem of terrorism.

First, they can do nothing or simply engage in defensive measures, e.g. tightening security by fortifying embassies, securing borders or screening airline passengers.

Second, they can engage in targeted responses, e.g. striking terrorist training camps, promoting opposition groups or capturing high profile terrorist leaders.

Third, they can opt for the use of military force with the goal of eradicating terrorist groups, eliminating the governments that harbor them, and preventing the groups, including potential sympathizers, from carrying out future attacks.

For years it was thought that "soft" responses to organized violence increased such activity while "harder" more forceful ones made it more difficult for terrorists to conduct their operations.

Whether hard tactics actually decrease terrorist violence, however, has long been a matter of contention. As several scholars have observed, offensive measures may be undertaken to prevent terrorist attacks but the tactics sometimes have competing effects. While they may make it more difficult for terrorist organizations to operate, they can also drive a hard core further underground where they become more committed and more deadly.

In addition, cracking down may increase grievances and terrorist recruitment.

My research suggests that targeted measures such as capturing or killing symbolic figures, like Saddam Hussein, may have a mitigating influence on transnational terrorist activity. It may be that the removal of leaders like Saddam or bin Laden has a demoralizing effect and makes more difficult terrorist recruitment or their neutralization may simply have an effect on subsequent operational planning.

While the Obama administration can take credit for the decisions that led to the decline in worldwide terrorist incidents documented in this week's State Department report, national security officials would also be wise to remember that the dips don't last forever. The evidence suggests that terrorist organizations adapt, regroup and frequently find new sanctuary.

The recent decline in terrorist incidents carried out by sub-state actors is also regrettably offset by the contemporary rise of state-sponsored violence.

The primary threat to world peace today comes, not from non-state actors, but rather from rogue regimes like the one in Iran that promote instability and violence to expand their own arc of influence.

There is evidence to suggest how best to manage this problem as well. Let's hope Obama and Romney are reviewing this research, too.

(Ivan Sascha Sheehan is the Director of the Negotiation and Conflict Management graduate program in the School of Public and International Affairs at the University of Baltimore. Follow him at www.professorsheehan.com.)

(United Press International's "Outside View" commentaries are written by outside contributors who specialize in a variety of important issues. The views expressed do not necessarily reflect those of United Press International. In the interests of creating an open forum, original submissions are invited.)