The Associated Press

FILE - In this June 10, 2012, file photo, supporters of the extreme right-wing Golden Dawn party, attend a pre-election rally at the northern port city of Thessaloniki Greece. Bankers, governments and investors are starting to prepare for Greece to drop the euro currency, a move that could spread turmoil throughout the global financial system. A Greek election on Sunday, June 12, 2012, will go a long way toward determining whether it happens. (AP Photo/Nicolas Giakoumidis, File)

By MATTHEW CRAFT AP Business Writer

NEW YORK (AP) — The unthinkable suddenly looks possible.

Bankers, governments and investors are preparing for Greece to stop using the euro as its currency, a move that could spread turmoil throughout the global financial system.

The worst case envisions governments defaulting on their debts, a run on European banks and a worldwide credit crunch reminiscent of the financial crisis in the fall of 2008.

A Greek election on Sunday will determine whether it happens. Syriza, a party opposed to the restrictions placed on Greece in exchange for a bailout from European neighbors, could do well.

If Syriza gains power and rejects the terms of the bailout, Greece could lose its lifeline, default on its debt and decide that it must print its own currency, the drachma, to stay afloat.

No one is sure how that would work because there is no mechanism in the European Union charter for a country’s leaving the euro. In the meantime, banks and investors have sketched out the ripple effects.