Given the task definition and input, reply with output. In this task, you are given a statement spoken by a politician in natural language. Your task is to generate the subject of the discussion for the given statement. The subject generated is not necessarily a part of the given input. Your answer should contain one or more words.

The Boston Marathon bombing is the fifth case in which U.S. government officials examined individuals potentially involved in terrorism and felt they were no threat and they went on to carry out terrorist murders.
terrorism