Obama urges 'constructive response' amid Ferguson unrest

WASHINGTON (Reuters) - President Barack Obama asked Americans on Tuesday to be "constructive" by engaging in debate about racial tensions and law enforcement, after a white policeman was cleared in the fatal shooting of an unarmed black teenager in Ferguson, Missouri. Obama, responding to the rioting in the St. Louis suburb, said demonstrators who engage in criminal acts should be prosecuted. (Editing by Peter Cooney)