OFFA, Nigeria ? When President Donald Trump announced U.S. airstrikes in Nigeria on Christmas night, he declared that his newly rebranded War Department had conducted ?numerous perfect strikes? against ?ISIS Terrorist Scum.? But warheads in four of the 16 Tomahawk missiles that were fired that night appeared not to explode, according to Nigerian officials, analysts and imagery reviewed by The Washington Post. Residents said one of the unexploded munitions landed in an onion field in the village of Jabo, in northwest Nigeria, while another hit residential buildings in Offa, around 300 miles to the south. The third Tomahawk crashed in an agricultural field outside Offa, according to a state...