BRUSSELS, Sept. 16  Belgium has given the world Audrey Hepburn, René Magritte, the saxophone and deep-fried potato slices that somehow are called French.

But the back story of this flat, Maryland-size country of 10.4 million is of a bad marriage writ large  two nationalities living together that cannot stand each other. Now, more than three months after a general election, Belgium has failed to create a government, producing a crisis so profound that it has led to a flood of warnings, predictions, even promises that the country is about to disappear.

“We are two different nations, an artificial state created as a buffer between big powers, and we have nothing in common except a king, chocolate and beer,” said Filip Dewinter, the leader of Vlaams Belang, or Flemish Bloc, the extreme-right, xenophobic Flemish party, in an interview. “It’s ‘bye-bye, Belgium’ time.”

Radical Flemish separatists like Mr. Dewinter want to slice the country horizontally along ethnic and economic lines: to the north, their beloved Flanders  where Dutch (known locally as Flemish) is spoken and money is increasingly made  and to the south, French-speaking Wallonia, where a kind of provincial snobbery was once polished to a fine sheen and where today old factories dominate the gray landscape.