Threat of Greek euro exit could complicate ECB's quantitative easing

The return of the idea of a Greek euro exit, as boogeyman or genuine threat, comes at a particularly difficult time, dangerously complicating the already fraught advent of full-scale quantitative easing in the euro zone.

A parliamentary vote, set to begin next week, to replace the Greek president may trigger general elections in the new year, elections that the anti-bailout party Syriza could well win.

"We shed blood to take the word 'Grexit' away from the mouth of foreigners, and Syriza is bringing this word back to their mouths," Prime Minister Antonis Samaras said, using once more the highly emotive term for a Greek parting of ways with the euro project.

The very idea, much less its invocation by the prime minister, panics Greek markets.

Even beyond Greece's own grave difficulties, should Syriza win an election, it would shortly enter into negotiations, if not conflict, with the troika of the European Commission, the International Monetary Fund and the European Central Bank over the terms of the bailout. That does not have to end with a euro line-up change, but the term and the idea will be batted about, with predictable results.

Almost no matter how you slice it, Greece, with a quarter of its population unemployed and having lost a quarter of its economic output, is poorly positioned to shoulder its debt load.

While Syriza has backed off from euro exit as a position, it did in May call for a write-off of almost a third of Greek debt, and in September for euro-zone debt relief for the country, perhaps by replacing existing debt with new bonds linked to gross domestic product growth.