Sunday's Greek election, explained

Greece is having an election on Sunday! Yes, they had a legislative election in January. And yes they had a big referendum back in July. But the economic and political crisis in Greece is sufficiently severe as to require yet another round of voting. And while back when the election was first called it looked like it would be an easy win for Prime Minister Alexis Tsipras, polling now shows a neck-and-neck race with his main opponent slightly favored.

At this point, both of the main parties favor accommodating demands from Greece's European creditors so the election is unlikely to spark a new round of economic and political chaos. But this is Greece, and Tsipras and his Syriza party have surprised outsiders many times before so don't entirely count economic and political chaos out.

Who is running?

There are two leading parties in the election:

• Syriza, the party that's been in power since early 2015. They came into office promising to rip up previous austerity agreements with European creditors, but were forced to make a humiliating climbdown this summer after it became clear that they didn't have any leverage.
• New Democracy, the traditional center-right party that governed before Syriza took office. There used to be huge policy disagreements between New Democracy and the far-left Syriza, but after Syriza's flip-flop on the austerity issue they disagree a lot less.

There's also PASOK, the formerly dominant center-left party that was marginalized by Syriza's rise, and which also supports accommodating the Germans. There's Potami, a newish centrist party that's never held office. There's Popular Unity, which consists of former Syriza members who opposed the European deal. And there's the neo-fascist party Golden Dawn.

What is going to happen?

The polls show a tight race between Syriza and New Democracy, followed by a close bunching of the smaller parties.

That's a big change from the immediate aftermath of Tspiras making a deal with Greece's creditors. For a moment during the summer, he was the absolute master of the Greek political scene having marginalized his rivals to both his right and his left. The high-profile confrontation with European finance ministers cast Tsipras as the embodiment of Greek national interests. The subsequent electoral campaign seems to have succeeded in allowing New Democracy to re-active the underlying ideological disagreements in the Greek population — consolidating most of the right-wing vote behind them while most of the left-wing vote goes for Syriza.

How does the election work?

Greece elects a 300-person parliament on a proportional basis, but with two significant twists.

• Parties that get less than 3 percent of the vote get zero seats in parliament.
• Whichever party gets the most votes gets 50 seats.

These deviations from proportionality can be very significant. The most recent poll, for example, shows Potami securing about 4.6 percent of the vote which should be good for 12 seats. But if Potami loses half its support and get 2.3 percent of the vote, they don't get six seats — they get zero seats.

That same poll showed Syriza with 31.7 percent of the vote and New Democracy with 30.9 percent of the vote. In a purely proportional system, that would leave Syriza and ND with basically the same number of seats. But in the actual voting system that projects out to 134 seats for Syriza and just 82 for New Democracy.

In other words, while the neck-and-neck race for first place between Syriza and New Democracy isn't quite as consequential as it would be in a zero-sum election (like a US presidential race) it's a much bigger deal than it would be in a more proportional system.

Is there going to be an exciting new crisis?

Probably not. It looks like the election will either allow a Syriza-PASOK left-wing coalition to secure a majority or else will allow an ND/PASOK/Potami center-right coalition to secure a majority.

The big background to all of this is that whatever their disagreements, these four parties all fundamentally agree that Greece should continue participating in the Eurozone and that means acceding to the key demands of Greece's creditors. The creditors, in turn, have a set of prescriptions that are sufficiently rigorous as to deny the Greek government many choices to make. The parties that want to break with the EU — Golden Dawn and Popular Unity — are both looking marginalized.

Consequently, it sure seems like there shouldn't be a crisis.

That said, you could imagine a situation in which the numbers work out such that the only way to form a majority would be to have a cabinet that included both Syriza and New Democracy. So-called "grand coalition" governments of that sort are commonplace in some countries, but can be tricky to get off the ground where they haven't existed before. Given the circumstances of the bailout deal with Europe, the actual policy differences between Syriza and ND are modest but there's no history of cooperation between these parties and the differences in social bases of support and self-conception between a radical left party and a conservative establishment party are large.

If a grand coalition becomes necessary, but coalition talks get difficult, you could start to see rumblings of complaint from Brussels, Frankfurt, and Berlin and a new round of economic uncertainty.