Random police searches of riders' bags to deter terrorism in the nation's largest subway system do not violate the Constitution and are a minimal intrusion of privacy, a federal judge ruled Friday. "The risk of a terrorist bombing of New York City's subway system is real and substantial," U.S. District Judge Richard M. Berman said in a 41-page ruling tossing out a lawsuit brought by the New York Civil Liberties Union. Citing testimony that up to 50 percent of terrorist acts were directed at transportation systems, he said the need to implement counterterrorism measures was "indisputable, pressing, on-going and evolving."...