Analysts say a messy divorce could lead to higher borrowing costs for weaker economies, plunging countries such as Spain and Italy deeper into recession.

The financial ripples could reach across the Atlantic, shaving as much as one percent off U.S. growth. Enough, says economics professor Peter Morici, to halt an already tepid U.S. recovery.

"We are only growing at about 2 percent a year right now," said Morici. "If we took another half a point off that, we're getting down to a level that can't be sustained. The economy could likely tumble into a recession."

Despite its minimal exposure to Greece, analysts say the threat of a double dip recession in the world's largest economy would be enough to roil already shaky financial markets.

Banks with greater exposure to European debt could see a run on deposits - some would face outright collapse.

Even faster growing economies in Asia can expect sharp declines as exports to the West dry up.

Ironically, Morici says Greece would be better off with a carefully managed exit from the monetary union. But he doesn't think that will happen.

"I expect the Greeks to elect the government that will keep them in the eurozone, and that they will implement the austerity program and that Greece will continue to cycle downward," he said. "This time next year, we'll be talking about 25 percent unemployment in Greece, much more than 50 percent youth unemployment, young professionals leaving the country and Greece slipping into developing country status."