Posted on December 26, 2011 9:36 PM

On  Christmas Day, churches were bombed in five Nigerian cities — Madalla,  Jos, Kano ,  Damaturu, and Gadaka — leaving dozens, perhaps hundreds, dead or  wounded. The killings were apparently the latest handiwork of the violent  Islamist group Boko Haram, and they show an increased level not only of  violence but also of sophistication, since the explosions were coordinated  and widespread, including the northwest, north, and center of the country.

These killings mark a further escalation  in the growth of radical forms of Islam in Africa ’s  most populous country. Muslims are a majority in the northern part of Nigeria ,  Christians are a majority in the south, and the two are about evenly mixed in  the middle belt, which has often been the scene of violent conflict. This  conflict has tribal and regional dimensions and involves political power,  land, and resources, but there is also persistent religious tension.

Beginning in 1999, sharia law, hitherto  applicable only to matters of family and personal status, was imposed in  twelve northern states, effectively making Islam the de facto official  religion in those states, in contravention of the federal constitution. Kano  State formed a 9,000-strong Hisba (sharia-enforcement) force. Conflict over  sharia led to thousands of deaths.

At about this time, a group named  al-Sunna Wal Jamma, and nicknamed “the Taliban,” began attacking  Christian settlements in Borno State from bases in the hills of neighboring  Cameroon. In January 2004, the group led a violent uprising in Yobe State,  displacing 10,000 people before federal forces succeeded in quashing it. In  January 2007, Alhaji Bello Damagu, the publisher of the Daily Trust newspaper, was charged in  the Abuja High Court with receiving money from al-Qaeda to fund the Nigerian  Taliban, including payment for people to go for terrorist training in  Mauritania. In early 2007, there were further attacks on the police in Kano  by a group calling itself the Taliban, leaving dozens dead.

The Nigerian Taliban’s current  official name is Jama’atu Ahlis Sunna Lidda’awati wal-Jihad, but  it is more usually known by its nickname, Boko Haram, which translates  roughly as “Western civilization is forbidden.” In late July  2009, around the town of Maiduguri in he northwest, it attacked police  stations, prisons, schools, churches, and homes, burning almost everything in  its path.

The violence spread to Borno, Kano, and  Yobe, where Boko Haram treated as infidel anyone — Christian or Muslim  — who did not conform to its views. Christians were a particular focus  of the violence. Many were abducted and forced, under threat of death, to  renounce their faith. The riots continued for five days before police were  able to stop them, and 700 people were killed in Maiduguri alone.

One arrested Boko Haram member,  23-year-old Abdulrasheed Abubakar, confessed to receiving $5,000 and military  training in Afghanistan, with the promise of $35,000 on his return there. On  Aug. 9, 2009, the group released a statement aligning itself with al-Qaeda  and calling for jihad in response to the killing of its leader, Mallam  Mohammed Yusuf. There are also reports that some of its members have trained  with militants in Mali linked to the organization al-Qaeda in the Islamic  Maghreb (AQIM).

Boko Haram has now added bombing to its  tactics. In August 2011, it claimed responsibility for the suicide bombing of  the U.N. headquarters in Abuja, Nigeria’s capital, which killed 23  people. While it continues to attack security forces and outposts of Western  influence, it is focusing its major attention on killing and displacing  Nigeria’s Christian population, which, at some 80 million, is the  sixth-largest in the world. It is also picking Christmas as a focal time for  attacks, a practice being followed by its international allies. In 2010, it  attacked five churches in Jos as the congregations were celebrating Christmas  Eve.

Boko Haram has declared that it is in a  “holy struggle to oust the secular regime and entrench a just Islamic  government,” and that it will “hunt and gun down those who oppose  the rule of sharia in Nigeria and ensure that the infidel does not go  unpunished.” Its increased sophistication and contacts with other  terrorist groups make it a threat not only to the country’s Christians  and traditional Muslim leaders, but to the stability of Nigeria as a whole.

—  Paul Marshall is a senior fellow at the  Hudson Institute’s Center for Religious Freedom and co-author, with  Nina Shea, of the just-released Silenced: How Apostasy &  Blasphemy Codes Are Choking Freedom Worldwide (Oxford University Press, 2011).