OUTSIDERS find the Polish-Lithuanian spat the most incomprehensible in Europe. How come two countries with so much common history and so many common interests get on so badly? Is it just the appalling personal chemistry between some senior officials? Or is it, absurdly, about spelling? Poles in Lithuania want to spell their names using letters like ł and ę in official documents. (We can't use them, or most other diacritics, in the print edition of the Economist because our typeface doesn't have those characters).

I have not met any Lithuanian, even on the nationalist fringe, who believes that the authorities in Vilnius have handled this issue absolutely perfectly from the very beginning. Lithuanian politicians have habitually promised more than their parliamentarians are willing to vote for, or their officials are able to implement. It is easy to see why Poles feel cross about that.

But the real problems lie deep in history. It is only the symptoms, not the causes, that are on the menu of the current spat. To get a flavour of what's going on, try reading this sour commentary, or this more balanced piece (both in English) on the Lithuanian Tribune website. It takes apart a recent piece (link in Polish) in Rzeczpospolita (a leading Polish daily) by Jerzy Haszczynski, which accuses Lithuania of wobbling towards Russia. The Lithuanians remember that the Polish minority in 1989-91 was used by Soviet loyalists to try to derail the independence cause. The argument soon goes back to who did what in 1831, and before that to the joint Lithuanian-Polish state of the early modern era (which both sides remember differently).

As I pointed out in my column in European Voice (the Economist's sister paper in Brussels) one big problem is that Poland is big (nearly 40m) and Lithuania is small (3m). Poles are very good (quite understandably, given their history) at seeing themselves as victims. They find it much harder to understand that some of their neighbours find them quite intimidating, linguistically, culturally and even politically. Another important psychological factor is that Lithuanians have learned through their own ghastly historical tragedies that stubborness pays off, whereas weakness is penalised. A concession to Poland on a matter that (at least in their eyes) is of vital national importance would send a signal to Russia that Lithuania can be pushed around. The result is a siege mentality in Lithuania, and outrage in Poland at promises unfulfilled

It is possible to detoxify these kinds of relationships. But it takes a lot of effort on both sides, whereas politicians so far seem far keener on posturing aggrievedly than trying to be constructive . For the time being, the best on offer is containment. The news that NATO's Baltic air policing mission is to be extended, in effect indefinitely; and the inching forward of the Polish-Lithuanian gas pipeline, shows that the broader concerns are not being forgotten.

The latest twist is that the OSCE's minority-rights commisioner Knut Vollebaek is looking at the issue. He visited both countries late last year and will do so again. His recommendations are private, but they are thought to include a mixture of points about process and substance. On process, the most useful thing for now would beto lower the rhetorical temperature, on the lines of "if you don't have anything constructive to say, then better not say it.". On substance, an important point is to remind the Lithuanians is that human-rights questions are not about reciprocity. This is about a government treats its own people, not about how it gets on with its neighbours.

The most easily fixable point may be on the spelling issue in documents. The right to spell one's name in the standard Latin alphabet (including the letter 'W' which does not exist in Lithuanian) is hard to contest. This is not just a problem for Poles: it's a nuisance if your name is Williams). And the law is probably against Lithuania on this one. The signage issue is more tricky: getting local authorities to accept that a shop can be called a Sklep (in Polish) will be hard. The question of property restitution in the Vilnius region is thornier. It is difficult in theory because its pre-war status, under Polish rule, is seen as an occupation by the Lithuanians. In practice, the problem is more about what might politely be called "administrative capacity" in the public institutions concerned.

But by far the most important issue is education. Lithuania is trying to improve the quality of Lithuanian-language teaching in schools (amid a wrenching decline in school numbers) and has required the Polish-language schools to teach more subjects in Lithuanian. This has sparked a furious protest by local Poles, readily echoed in Warsaw.

And that, in fact, is the nub of the problem. So long as Polish-Lithuanian relations are hostage to the grievances (real, exaggerated or wholly imagined) of the local Poles, and in particular of their sometimes dodgy local leaders, this row will continue to poison the air. The local Poles' ability to call up heavy artillery from Warsaw in local disputes makes the Lithuanian leadership feel beleaguered and even betrayed: they start questioning the loyalty of their ethnic-Polish compatriots to the Lithuanian state itself. The best thing that Poland can do is to make sure that those fears seem groundless.

The most disastrous turn of events would be if Polish public opinion started pressuring politicians to take an even tougher stance. That has not happened yet, for which the Lithuanians should be grateful. But it could. Many will be wishing Mr Vollebaek the best of luck in his thankless task.