The Rhode Island chapter of the American Civil Liberties Union is suing the town of Smithfield to keep it from enforcing a ban on anonymous political literature. The lawsuit filed Tuesday says the town has said it will enforce the law, despite a 1995 decision by the US Supreme Court that struck down a similar law in Ohio and upheld the right to anonymous free speech. The Police Department did not respond to a message seeking comment, and the attorney general’s office, also named in the lawsuit, did not comment. Last year, Smithfield police charged a political consultant with distributing anonymous campaign materials.