The sticking point, the officials said, is that Assange published top-secret documents but did not leak them. Anonymous Justice Department officials described the legal complications to the Post as a "New York Times problem," meaning that if the department indicted Assange, it would also be compelled to prosecute news organizations and journalists who published classified material.
The federal government has charged individuals who leaked classified information, including fugitive former security contractor Edward Snowden and private Chelsea Manning, under the Espionage Act. Manning was convicted in July and later sentenced to 35 years in prison.
A grand jury continues to investigate WikiLeaks' release of classified military and diplomatic documents, the U.S. officials told the Post.