Sheesh, the euro-types have given Greece a going-over. If those perennial fudgers and compromisers are willing to go as far as that, Tsipras clearly overplayed his hand catastrophically (and of course got right up their noses at a personal level). Can it possibly stick? - there's such a thing as a deal that is too good for its own good.
Anyhow, to the history books. 5th-century Athens bore some resemblance to 21st-C Brussels, the hub of a semi-imperial set-up, administering a more-or-less compliant collection of diverse and once-proudly-independent city-states and regional entities. Some they had taken by conquest, others had originally been fellow members of the Delian League before it morphed into the Athenian pseudo-empire. In any event they were pretty much obliged to accommodate the wishes of Athens which, for its part, was bluntly guided by its own self-interest, sometimes far-sighted and moderately enlightened, sometimes less so.
Melos was an island which sought to persuade Athens not to enforce punitive levels of tribute. A debate ensued: the famous Melian Dialogue, as written up by Thucydides, which starts off with some fairly even-tempered exchanges, the Melians attempting to achieve their goals by rational argument, the Athenians courteously responding - giving details - that they didn't see it that way.
It didn't end well.
The Melians should have known. Although by that time Athens was a democracy (of sorts), and public morality was evolving towards something we'd recognise in the Judeo-Christian tradition, the massive residual influence of the Homeric tradition was still out there. Homeric morality is simple: only one thing counts, and that is Results. How you achieve them may be more or less decorous, but a successful Result trumps all nicer considerations and finer feelings. Initially the results in question were to the benefit of a noble family, later to a city-state, and later still by extension to a wider civic entity. As the Athenian empire became more complex, it became ever more difficult to determine what exactly was in its best interests (the birth of politics and the rise of the esteemed counsellor alongside the great warrior): but that's not the point.
Tsipras and his chums are Marxists, or so we are told. Greek Marxists, of all people, ought to have a clear historical perspective on this stuff. Apparently not: and now his people will be getting the Melian treatment in no uncertain terms. What price a classical education, eh?