A Slovak Foreign Ministry statement fumed last week: "Some Czech politicians, even after an independent Slovak republic has existed for four years, have been unable to rid themselves of a feeling of superiority and tutelage, on the basis of which they comment on internal political events in their neighbour."
At the heart of the dispute lies an awareness on both sides that the Czech Republic and Slovakia have gone down markedly different paths since they peacefully laid to rest Czechoslovakia at the end of 1992.
The Czechs, though increasingly burdened with economic problems, are front-line candidates to join the European Union and Nato, while Slovakia is in the West's bad books, almost entirely because of the antics of its Prime Minister, Vladimir Meciar.
The row reached its zenith on Tuesday when Mr Meciar, who is viewed by his domestic opponents and foreign critics as an authoritarian bully, called off a visit to Prague. It would have been his first since Slovakia gained independence.
His spokeswoman said he was reacting partly to a statement attributed to the Czech Prime Minister, Vaclav Klaus. The Prague media had quoted Mr Klaus, who has a reputation for arrogance, as saying that his government had more important things to do than prepare for a Meciar visit.
Pouring fuel on the flames, Slovak radio quoted the Czech President, Vaclav Havel, as diagnosing Mr Meciar as a case of "peculiar paranoia". A furious radio commentator told listeners: "Havel has merely confirmed that he has joined the line of Czech presidents who hated Slovakia and the Slovak nation, such as Benes and Novotny [presidents of Czechoslovakia before and after the Second World War]."
Matters grew more serious when the Slovak government indicated it might try to block Czech accession to Nato on the grounds that the Czech and Slovak states were still arguing over the terms of the 1993 divorce settlement. As the Slovaks pointed out, Nato has advised candidate-members to have no outstanding disputes with their neighbours.
Among the unresolved issues are the cross-ownership of banks and division of CzechSlovak gold reserves and state treasure. But it is doubtful that these matters are serious enough to give Nato second thoughts about inviting the Czechs to join the alliance in July.
Mr Meciar, aware that Slovakia faces exclusion from the first wave of Nato enlargement, is looking for a way to avoid the blame for what many Slovaks will see as a major diplomatic setback.
If, as expected, Hungary and Poland join the Czechs in receiving Nato invitations, Mr Meciar will stand accused of letting Slovakia lapse into isolation.
Yet he is already preparing an escape route. Slovaks will vote in a referendum next month on whether they want to join Nato, but Mr Meciar's supporters in parliament have slipped in a question on whether Slovaks want nuclear weapons and foreign troops on their soil.
Although Nato has no intention of making such deployments, a majority of Slovaks may vote "no". Mr Meciar could then claim that this justified staying out of Nato when the reality would be that Nato never wanted a Meciar-led Slovakia.