The Justice Department has been investigating Assange since 2010, when they began posting thousands of stolen documents by US Army intelligence analyst Chelsea Manning.
Former Attorney General Eric Holder and other Justice Department officials said that charges would be difficult because the site wasn't alone in publishing the documents, various newspapers also did.
Assange remains in the Ecuadorian embassy in London, hiding out of fear of extradition.
Last Week, CIA Director Mike Pompeo called out the website, saying it is "a non-state hostile intelligence service often abetted by state actors like Russia."
Russian President Vladimir Putin admitted after Trump's election that they "may have" helped with Wikileaks information.