"he wouldn't be facing 18 charges today" - I think it's pretty clear the US has been working on charging and imprisoning Assange since around the time of "Collateral Murder". They would have found something else!
Assamese already was facing a sealed indictment on other charges related to the Manning dump, charges that the Obama administration carefully drew up to avoid any 1st amendment implications. The charges being discussed here, being brought by the Trump administration, are the charges with first amendment implications.