The U.S. Department of Justice claims that Assange broke the law by receiving classified documents from a source, speaking with that source, possessing the documents, and publishing some of them. In other words, things journalists at news outlets around the country do every day.
If Assange is convicted under the Espionage Act, there will be nothing to stop the government from prosecuting other journalists who publish government secrets.
Take action to protect press freedom: Tell the Biden administration to drop the Assange case now.