Sens. Marco Rubio and Ted Cruz clashed over their opposing votes on a key surveillance bill during Tuesday night's GOP debate, with each senator trying to establish himself as the strongest on national security.Rubio accused Cruz of hampering intelligence agencies by supporting the USA Freedom Act, which ended the National Security Agency's vast collection of millions of U.S. phone records. That information could have been critical in investigating the shooting in San Bernardino, California, Rubio argued. "We are now at a time where we need more tools, not less tools," the Florida Republican said. "And that tool we lost, the...