PM Alex Tsipras is going to hold a referendum on whether Greece should take on more debt and make ever more swinging cuts. Is he playing a trump card here?
He is not saying that the referendum will be binding, but if it goes the way he expects to - a rejection of any more loans/debt he will have a strong hand to play. He will be able to walk away from anything the Troika want and he will have the backing of the Greek people.
It could go the other way, of course, but then he could claim that put everything on the shoulders of the Greeks, they will, after all, have voted for Christmas.