The crisis is this: The Sahara Desert is advancing southward into wide swaths of the Sahel, eliminating grazing lands, forcing populations to move, and igniting new conflicts over land and water. Lake Chad, once a principal source of sustenance for millions of people, has shrunk by more than 90 percent since the 1960s. The crisis is called by some specialists the world’s most complex humanitarian disaster. The web of local conflicts creates opportunities for Boko Haram and other extremists to exploit, recruiting desperate youth as fighters.

Partners in Africa

Nigeria is a vital partner in addressing this crisis, and is better placed for that role than a decade or two ago. After generations in which Nigeria has suffered from corruption and from frequent military rule, the country has made real progress toward a more stable, democratic system. Sustaining that progress, and supporting Nigerians’ efforts to solve their own problems is one of the most potent steps the United States and its allies can take to support democratization and stability across the African continent.

With U.S. policymakers often wary of unilateral U.S. commitments abroad, the good news is that the best way to help Nigeria and the Sahel region is in a broad partnership with Africans and other international contributors. Key partners include the Multinational Joint Task Force, which has fought Boko Haram and other militant groups around the Lake Chad Basin. Nigeria has taken a lead role in the force, which also includes troops from Benin, Cameroon, Chad and Niger. Nigeria also is a major contributor to peacekeeping operations by the African Union and the United Nations. A relatively new regional partner is the Group of Five for the Sahel, composed of Burkina Faso, Chad, Mali, Mauritania, and Niger. Former Secretary of State Rex Tillerson this year called the new group, like the task force, instrumental in achieving “African-led solutions to terrorism and instability.”

Boko Haram: Still a Threat

President Buhari declared a “technical victory” over Boko Haram in December 2015, and its territory is largely confined to pockets deep in forested areas. Yet the group has not been extinguished. Its recent attacks, including suicide bombings and the February kidnapping of school girls in the northeastern town of Dapchi, show that it can still cause instability, and retains the potential to revive.

The next phase of defeating Boko Haram and other extremists is to help Nigerians as they stabilize and rebuild shattered communities in the northeast. One critical challenge is resettling nearly two million displaced people who fled Boko Haram or the fighting of recent years. Another is re-integrating those former extremist fighters who have renounced violence into their old communities, many of which still are suffering from losses amid the war between the state and Boko Haram.

One critical need: Nigeria must deal with vigilante groups that it helped create and arm, under the name of the Civilian Joint Task Force, to fight Boko Haram. The state gave these local groups of young men uniforms, weapons and salaries. But it never made them subject to laws governing security forces. Now these groups lack any clear role or future—a serious security threat. In the northeastern state of Borno alone, vigilante groups say they have more than 26,000 members.

How the U.S. Can Help

The United States currently provides training and technical help to the multinational military force. This should continue. But the continuing attacks, even after a broad, military victory, underscore that the crisis cannot be resolved by military means alone.

America’s security assistance must be complemented by diplomacy to encourage governments in the region to build trust and cooperation among the communities—farmers, herders, and disparate ethnic or religious groups. They must build the same cooperation among such communities and the vigilante and security forces, so that they all can withstand continuing sporadic assaults by extremist groups.

Two specific areas of cooperation are essential. One is to achieve, for the first time, effective, community-oriented policing. Military forces, which now are the main security resource, cannot sustain stability. Only a modern police force can do that. The second is stronger local methods for resolving the inevitable conflicts over how to more effectively share the shrinking resources such as land and water. To advance both of these goals, USIP has launched pilot-scale, community-based dialogues between local communities and security forces in Nigeria and four other nations of the Sahel.

In such efforts to build relationships between communities and governments, a particular need in Nigeria is to engage Nigeria’s powerful state governors—a vital part of building people’s hopes that the state and federal governments can help them improve their lives.

One other way that America can help is to work across the Sahel to focus national, regional and international policymakers on addressing a fundamental cause of the crisis: the damage that Lake Chad’s shrinkage is causing to vulnerable communities.

Ahead: Nigeria's 2019 Elections

President Buhari has declared that he will run for a second term in next year’s elections. Although 2015 marked Nigeria’s first-ever democratic transfer of power to an opposition candidate, Nigerian elections often are conflictual and violent, and marred by irregularities and political intimidation. Nigeria’s conflicts could be inflamed by the elections or could become the excuse not to hold them at all.

With presidents across Africa testing the limits of democracy—postponing elections and extending their terms in office—timely and sound elections in Nigeria are critical. Their importance will only grow following the recent months’ violent protests and contested result from the presidential vote in Kenya. U.S. support for Nigeria’s elections, via diplomacy and through democracy and governance programs, should be sustained.

Oge Onubogu is a senior program officer for Africa programs at USIP. Chris Kwaja is a USIP senior advisor and a professor at the Center for Peace and Security Studies at Modibbo Adama University of Technology in Yola, Nigeria.