FDR used the radio to speak to the American people. During this time, no individuals had television, movies were just becoming a large thing, so there was no other way to reach the American people all at once other than a news paper. So by FDR doing over the radio and speaking to the American citizens who almost all universally had radios or access to them, it built trust and it built a unity because it showed the American citizens he cares for them.
