The state of emergency declared Tuesday by President Goodluck Jonathan of Nigeria is a clear signal to the country's large armed forces that it is time for them to take decisive action.
The declaration covers three of Nigeria's 36 states -- Adamawa, Borno and Yobe -- which are in the northeast and have been the site of a violent standoff between the central government and militant Islamists, roughly aligned in a shadowy movement called Boko Haram. It is anti-Western, anti-Christian and anti-moderate Islamist -- yet roughly half of Nigeria's 170 million population is Christian and most of its Muslims are moderate. Boko Haram focuses its rebellion on the education system, which it considers opposed to its kind of Islam.
Hundreds of people have died in fighting between the radical Islamists and Nigerian security forces. Churches and mosques have been destroyed. The whole affair is yet another chapter in Christian-Muslim competition in Nigeria, dating from independence in 1960, for control of the oil-rich state.
For Mr. Jonathan to mobilize Nigeria's troops, an estimated 100,000, against Boko Haram in a far corner of the country will not be easy. The matter is complicated by the fact that Nigeria's northeastern states border on Cameroon, Chad and Niger, which have loose control of their territories.
Nigeria's military normally focuses on subjects other than internal defenses. There have been numerous military coups d'etat and presidents in Nigeria's history. The military pays close attention to collecting a large share of the country's oil wealth. It has participated credibly in global peacekeeping operations, for which it is paid well. Nonetheless, if properly focused, it is probably capable of bringing Boko Haram into line and restoring peace.
It should be the troops' job, of course, with no role for the U.S. Africa Command, which has already been over-involved in Libya, Mali and Somalia and is chasing the Lord's Liberation Army in Central Africa. Mr. Jonathan is right to give the mission to his own military.