Nigeria, Oct. 28 -- Nigeria recently partially closed its border with Benin in an effort to stem the smuggling of rice. It then went on to close its land borders to the movement of all goods from Benin, Niger and Cameroon, effectively banning trade flows with its neighbours.

Border closures are not new in Africa. But Nigeria's actions raise important concerns about the seriousness and prospects of regional integration in Africa.

Nigeria acted just three months after it had signed the African Continental Free Trade Agreement. With 55 member countries, a combined GDP of $2.4 trillion and a total population of 1.2 billion, the agreement will create the world's largest free trade area. Its aim is to promote intra-Africa trade, which is abys...