Did Belgian bungling over jihadists lead to the Paris attacks? Are French jibes at their small, northern neighbor a mere tactic to disguise failings closer to home?
At government level, a blame game between Brussels and Paris after the killing of 130 people on Nov. 13 by French and Belgian radicals has been played out in a language of diplomacy; not so this week in the press. Leading editorialists have declared war.
Le Monde, voice of the Paris establishment, upped the ante in its Tuesday edition by declaring Belgium "a nation without a state", where power is so devolved among local fiefdoms that it has neglected national security— to its neighbor's cost.
La Libre Belgique, irked by "boundless French condescension" in offering to "help Belgium protect itself", denounced "grubby" finger-pointing. And since Le Monde brought up a bungled 1990s child rape-murder case that exposed Belgian police to ridicule, the Belgian paper recalled another case that embarrassed France.
The tit-for-tat between leaders has been more restrained, and officials on both sides insist that cooperation is intense in efforts to track down those who organised the Paris attacks.
Last week, Belgian Prime Minister Charles Michel named no names in chiding those who "insult our security services" after French President Francois Hollande said the attacks were planned in Belgium. But he did, pointedly, tell parliament in Brussels that it was Belgian intelligence that foiled a follow-up attack.
Sneers and touchiness in the columns of newspapers reflect a long tradition.
Le Monde declared "the Belgians are our friends, our brothers; we love their humor". True, the land of Tintin is a major part of the "French" tradition of comic strip. But the Paris paper chose to cite as evidence a topical "Belgian joke".
The Belgians are to the French what the Irish are to the British or Poles to Americans. Le Monde recalled "The Belgian suicide bomber", a classic — Belgian — cartoon much tweeted of late. He declares he will blow himself up: "But just this once."
Yet if Belgians like not to take themselves too seriously, criticism from their "big brother" to the south has hit a nerve.
Describing "nice little Belgium" as the "clearing house for jihadism", Le Monde said decentralization of power to prevent a break-up of the state into its French- and Dutch-speaking halves hampered coordination against militants: "This state without a nation," it said, "Risks becoming a nation without a state."
La Libre Belgique editor Francis Van de Woestyne found that hard to take from a country where the "racist" National Front (FN) leads the polls: "The criticism would be easier to accept if they came from a state without failings," he said, adding wryly: "But no doubt the FN leadership was trained in Belgium."
The Belgian riposte may be about to step up a gear.
Foreign Minister Didier Reynders tweeted a link late on Tuesday to a La Libre Belgique story which reported that he will launch a drive to "correct" the country's image abroad — especially in France.
Follow us on Twitter: @CNBCWorld