Old hands at litigation will tell you that if you are stuck for a strategy you can do worse than to imagine yourself in the other side's position, work out what it is that they would like you to do least and then do it. It is not the most constructive approach, of course, but it gives you a way forward and on occasion it can be surprisingly effective. It is also the approach which Mr Tsipras seems to adopt in his negotiations with the EU and it is worth looking to see how well it has served him.
Go back to the beginning, and how long ago it seems now, when Syriza and its allies won the Greek elections. The country was struggling, as indeed it still is, under austerity targets which it was not capable of meeting. It was the poor man at Europe's door, to be pitied certainly and thrown a crumb from time to time, but there was no doubt that all the power lay with the big battalions up north and that although the new government might achieve a little more by negotiation there was little it could really do to change things.
In his campaign to escape from that "reality", Mr Tsipras and his colleagues have played every trick in the book and some of them very aggressive ones. They have suggested Germany pay war reparations. They have confused the discussions with myriad proposals - sometimes contradicting each other. They have been tricky and aggressive by turns and then, to cap it all, they have attempted to move the goalposts by putting the EU's best offer to a referendum and having it rejected.
None of this sort of stuff is supposed to happen in the EU at all. It is a group of countries bound together by cultural links and common interest, a world where things are settled by a nudge here, a wink there and sometimes a little bung to smooth the process. The confrontational approach taken by Greece cuts right across the conventions by which it operates. That's why everyone tuts and uses words like "naive" and, "unsophisticated", expressions like "not playing the game". But actually. if you look at historical precedent, an unwillingness to play the game according to the old rules is often the mark of a winner. The successful soldiers are typically those who are just that bit more ruthless and more original than others. Think Napoleon. Think Guderian. Think Lawrence of Arabia. In politics too it the new approach which changes the dynamics. Think Lincoln, winning the Civil War by freeing the slaves. Think Thatcher, riding down thickets of vested interests to change the political status quo.
So what has this unconventional approach achieved for Tsipras. Will he keep his country in the euro at a more affordable price? Will he be forced to take it out and, if so, how will the transition be made? Writing on Tuesday morning it looks like out but this is a story which twists like an eel and it may look different by the time you read this. One thing is sure, however. He has succeeded in damaging the position of his opponents who now face a difficult dilemma. No, it is not to decide whether to allow Greece to remain in the eurozone or not. That is certainly difficult but behind it there is a more difficult question still. How far should the eurozone go to help Greece to recover from its current distress.
Simple compassion means that the EU should try to smooth the path of Greece through its economic troubles, even if that path should take it out of the euro, and the German governments references to humanitarian aid seem to recognise this. The EU cannot have its erstwhile citizens starving on the streets - particularly when it is conscious that by admitting Greece on fudged terms it was itself part author of the current debacle. Anyway we need their help in stemming migration across the Mediterranean and presenting a united front to Russian adventurism.
All that points to smoothing the path but alas there is a second prong to the fork. Suppose that Greece moved to the drachma in an orderly fashion or suppose even that it remains in the eurozone with much of its debt written off. What happens then when the governments of Portugal, Ireland and Spain meet their electors? Won't the demagogues call for an end to austerity and then cite Greece as an example of how it might work? What hope for the European model of austerity then? The best that can be hoped for is that the various electorates will regard the risk of having to leave the euro as too high a price for a reduction in debt.
It's hard to see the endgame but that doesn't take away from the fact that Mr Tsipras has put his opponents under pressure, something underlined by the way in which Germany and France are now using their own political and financial muscle to call the shots. And the EU Commission, the ECB and the IMF where does this mess leave them?
There is a story told in naval circles of a British warship coming into its home port. Enthusiastic to get home, the commanding officer, who had just been promoted lieutenant, brought it round too fast, overshot the channel and got stuck on a sandbank. It took some time to get off but with tugs and engines in full reverse they made it. It would have been better if the boat had no swung round and buried the propeller in the other side of the channel. The admiral commanding the flagship watched all this going on below him and and sent a signal to the Young lieutenant saying "what are you going to do now?". Seconds late he received his reply. It simply read, "Buy a farm". Perhaps it is an example that Juncker, Draghi and LaGarde should follow.Suggest a correction