The gov't can arrest you any time they want for any reason they'd like. Courts ultimately decide whether or not it was lawful. To answer your question. also...

"Under the First Amendment, laws "abridging the freedom...of the press" are invalid. Most states also have their own laws in place which protect reporters from having to disclose their sources and, in certain cases, unpublished materials. Some states have even included "free press" provisions in their state constitutions." ~ https://www.legalzoom.com/articles/can-a-journalist-be-force....

You can try and call yourself a journalist but you will need a court to uphold it.

You are free to believe whatever youd like but I choose to live in reality... Assange is no journalist.