The threat to Julian Assange is indeed a threat to all journalists everywhere and the American people. The US indictments (both preliminary and expanded) are against an non-citizen (Assange is an Australian citizen) for journalism he did outside the US.
The US government is clearly upset that WikiLeaks, under Assange’s direction, published clear evidence of war crimes the US committed. But what WikiLeaks published isn’t illegal (see the Pentagon Papers) and the US government knows this so it’s claiming illicit computer access instead, a case for which there appears to be no more evidence now then there was when the Afghanistan and Iraq war logs were initially published. The indictments are a matter of seeking revenge against Assange to punish him for his truth-telling and a warning to us all that we must not do similarly.
The charges against Assange relating to his journalistic WikiLeaks work must be dropped. If any other charges are pursued, we can evaluate their merit as we learn what those charges are. So far the only charges published are those having to do with what WikiLeaks published.