At least some U.S. officials want to play hardball over the North Korean interception of a RC-135S Cobra Ball aircraft that was flying about 150 mi. offshore observing preparation for upcoming missile tests. North Korea fired off two Rodong ballistic missiles, with the range to hit Japan, in February, and more tests are expected. "The North Koreans have been told that intelligence-gathering aircraft will continue flying, and they will be escorted by F-15s and F-16s," a senior Air Force official said. "They've also been told that if their fighters lock on again [the electronic prelude to firing a missile] our...