Although Euro alliance shows its strong determination to support Greece, they will not have to prepare a bailout for Greece, if the Greeks themselves choose to separate from Euro.
The Greeks will have to use Drachma again instead of Euro.
The value of the Drachma will be under 1/100th of what the Euro is now.
Before the general election of Greece, deposit in Greece has been withdrawn from banks.

The GDP of Greek economy has only three percent of the GDP of Euro alliance.
Even if EU loose Greece, the influence will not so serious for EU.
But there are two reasons to protect Greece from leaving EU.
Geopolitically speaking, Greece lies in front of Islam countries.
And another reason is that Greece crisis will lead to next crises in PIIGS countries.