SCOTUSblog has a very interesting discussion of Illinois v. Lidster, which will be argued November 5. Mr. Lidster was arrested for drunk driving after he was stopped at a roadblock set up by police who were seeking possible witnesses to a fatal hit-and-run accident that had occurred at the same location and time of day one week earlier. Whether the roadblock violated Mr. Lidster's Fourth Amendment rights under current Supreme Court jurisprudence is a close and interesting question. SCOTUSblog's post even links to the briefs.