BEFORE 9/11 there was Oklahoma City. Today marks the 16th anniversary of the second worst terrorist attack on American soil--and a sickening harbinger of the heartache to come. On April 19, 1995 domestic terrorists detonated a massive bomb at Alfred P. Murrah Federal Building. The result: carnage and chaos. By the end of the day, 168 people had been killed and hundreds more wounded. Among the dead was Antonio Cooper Jr. He was 6-months-old."I feel it's a necessity to be here," Antonio Cooper Sr. said Tuesday as he strapped a colorful bouquet of spring flowers to the chair bearing his son's












