The Assange case is stuck and embarrassing. How might one look at this issue as a professional mediator?
As things stand, the interests of Assange/Ecuador and UK/Sweden respectively largely coincide.
Assange/Ecuador want to use the issue to bolster their reputations and poke the US/West in the eye.
UK/Sweden want to carry out their legal obligations.
However, perhaps the interests of Assange/Ecuador will start to diverge (there might well be ways in which the UK can crank up pressure on Ecuador, eg by sending the Ecuador Embassy a hefty bill for the extra police needed to keep an eye on their building because a fugitive from injustice is improperly skulking inside it). Plus the charm of hosting Mr Assange may peak then dwindle for the Ecuadoreans.
Likewise UK/Sweden. The UK is on a hook caused by Sweden's legal processes. Can Sweden as a good EU partner help get rid of that hook or at least help the UK get off it?
The very greatest tool a mediator has is a simple little question: What if?
This question invites if not compels the feuding parties to think differently, to step back, to brainstorm, to imagine something different. Any by imagining something different, they can start to look anew at the true costs and benefits of the current deadlock, as compared to alternative outcomes.
So, what if all concerned started to look at alternative outcomes?
Assange has to accept that he can not be 100% safe from an extradition request from the USA other than (a) by hoping that the USA has not yet made one to the UK or Sweden, and (b) making a beeline to a country that has no extradition arrangement with the USA, then staying there for the rest of his life. Not much fun.
Ecuador has to accept that sooner or later Assange has to move out from its London Embassy. Why not sooner, as long as Ecuador does not get dishonoured/embarrassed in the process?
Sweden has to accept that the current deadlock is getting nowhere as a result of Sweden's legal processes, and costing the UK a lot of money that Sweden may not wish to pay.
The UK has to accept any outcome that gets the business sorted (ie if Sweden is happy, the UK should be happy). If Assange is demanded formally from the UK by the USA, he can amuse himself battling it out in the UK and European courts for a few years more - but no guarantees.
So is there an outcome that achieves all that?
Yes there is.
Sweden agrees to send its investigators to question Assange in the UK, perhaps in the Ecuador Embassy.
If Sweden is persuaded by his testimony to drop the extradition request and/or the substantive investigation into his alleged wrongdoings in Sweden, that's the end of it. Assange walks out on to the street, gets his passport back, and then takes his chances with any stray US extradition requests, here or anywhere else that will take him.
If, however, Assange does not give convincing answers and so Sweden decides to pursue the criminal case against him, Assange must agree in advance to surrender himself for prompt transfer to Stockholm accordingly. He has had the chance to put his case, and now must accept that a democratic country wants him to answer under due process of law for an earlier alleged transgression. Sweden may want to offer him legal aid and/or otherwise make it 100% clear that he will be given every opportunity to defend himself.
In either case, Ecuador and the UK can end their boring diplomatic stand-off with no loss of face.
Some of this would involve some deft quiet diplomatic footwork by all sides, so far often lacking. But one learns from one's mistakes.
Plus it (crucially) would require Mr Assange to take a deep breath and start to behave honourably and respectfully himself towards HMG and the authorities in Stockholm - harder, but not impossible if Ecuador says that his refusal to do so will give them little choice but politely andf firmly to send him on his way.
Anyone with any better ideas?