Goodluck Jonathan has been sworn in as Nigeria’s president, succeeding Yar’Adua, who died Wednesday. Yar'Adua was only able to fulfill half of his presidency before falling ill, causing speculation of a power struggle between rival religious and geographical groups. An unwritten agreement to keep peace in Nigeria keeps the presidency alternating between north and south. Many expect southerners will try to violate that agreement and seize power before their expected turn. While conditions have improved there since decades past, Nigeria has been home to some of the world’s worst intercommunal violence. Yar'Adua, 58, will be buried in a Muslim ceremony Thursday, in his northern home state of Katisna.