Once he was delivered to UK authorities I figured I did not need astrology to answer this. Yet, I believe the answer in the chart is clear.
Assange is L7, Mars. He is imprisoned in a foreign country. Mars is not only inside the turned house 12 (prison) but that same house is also the house of the government of a foreign country (the UK government), turned 10th from the 9th.
The question was asked by an American so the American government is L10, Saturn.
What happens to Mars next?
Mars squares Saturn. Answer: he will be delivered to the USA authorities. That is, extradited. A square depicts the complications of the case. There is a collection of light between Venus, Saturn and Mars, actually. Aptly describing him going from one authority to the other.
One would expect that an event like this would be shown by an opposition. But no, there is no significant resistance from Assange; he is helpless. His legal representation, Jupiter is not angular and is conjunct the South Node by antiscion; also helpless. The authorities have all the power. They are simply going through the motions of the process. A square is to be expected and easy considering the legal, as well as illegal (see comment on Mercury below) complexities involved.
Some extra details:
Mars is ruled by Saturn by exaltation and by Venus (the UK authorities) by sign. He is completely under their power, as the context dictates. Venus is in Julian Assange’s house showing strong influence in his affairs or life, also as the context dictates.
Mars and Venus are in mutual reception by sign, aptly describing the fact that Assange is “relatively” protected from the USA government while in a foreign country.
Mars disposits Saturn by exaltation showing, in theory, that Assange has a measure of power over Saturn, as indeed is the case by the nature of Julian Assange’s work. But Saturn is in its own sign, it will do whatever is self-preserving in the context and will, therefore, do with Mars whatever it pleases.
Mars is conjunct Neptune by antiscion. Indeed an earthshaking situation for him. Mars is conjunct the star Vindemiatrix which shows he is in an over-stretched situation. Basically, he does not stand a chance against his enemies.
Mars is in its detriment; not even he can help himself. There is no helping power in his situation at all. This is a completely hopeless chart.
Mercury also has a strong influence in Assange’s life and is close to the 10th cusp by antiscion so connects him to house 10. Since Mercury does not rule a relevant house I am inclined to read Mercury as a natural ruler here. Everything about Assange’s case is fraught with secrecy, double standards, backroom dealings and, as recently revealed: illegal spying inside the Ecuadorian Embassy. So, Mercury makes sense.