Hello from the Atlanta airport. I wasn’t planning on posting anything until I got to Siena, but this fast-moving Greek crisis is really something else. The latest:

“They were playing poker,” said Austrian Finance Minister Hans Joerg Schelling after the Eurogroup that runs the currency met on Saturday without their Greek counterpart to discuss how to limit the fallout. “But in poker, you can always lose.”

After five months of negotiations with a Greek government elected to end the pain of austerity measures, EU leaders left a summit in Brussels on Friday believing a deal was close to roll over bailout funding and let Athens meet a repayment to the IMF on Tuesday and further obligations over the coming months.

But Prime Minister Alexis Tsipras provoked consternation by returning home to call a referendum for next Sunday on the offer and urging voters, weary of years of debt crises, to reject it.

Not for the first time, EU officials said Greek negotiators across the table were themselves taken by surprise by news from Athens. “They heard about the referendum on Twitter,” one said.

“Tsipras messed up,” a euro zone official said. “We did everything possible. They chose to blow up when we were so close to settling this in a way that would allow them to sell it.”

Amid political drama in Greece, where a clear majority wants to remain inside the bloc, the next few days present a major challenge to the integrity of a 16-year-old currency bloc, which many blame for massive unemployment in countries outside Germany and its neighbors in the richer north and west of Europe.

“We must do everything we can to fight any conceivable threat of contagion,” German Finance Minister Wolfgang Schaeuble said after a meeting at which the group effectively called for capital controls to ring-fence Greek banks hemorrhaging cash.

It’s going to be bumpy week.