he Secret Service may try to force former FBI Director James Comey to answer pointed questions into a social media post he issued depicting an image of “8647,” but a U.S. attorney whom President Trump appointed will determine whether to prosecute Comey over the post. If Comey refuses to comply with their request for what’s known as a protective intelligence interview, the Secret Service leading the investigation into the Instagram post can apply for a subpoena through an assistant U.S. attorney. It’s that prosecutor who will determine whether the former FBI director is legally required to answer their questions, and...