What is the fine-grained topic of the following text: The public is invited to learn the remarkable story of Josiah Dubois Jr, an American attorney at the U.S. Treasury Department who played a crucial role in exposing State Department obstruction efforts to provide American visas to Jewish people trying to escape Nazi Europe. Only return the topic.
Josiah Dubois Jr's role in exposing State Department obstruction efforts to provide American visas to Jewish people escaping Nazi Europe.