It's election day in Israel. All across the country, a fierce battle for voters is underway, with the main protagonists being Prime Minister Benjamin Netanyahu and his Likud party, and his challenger from the Labor Party, Isaac Herzog.

Polls will stay open until 10 p.m. local time (4 p.m. EDT) and officials results should come out not long after. But if you're hoping for a quick answer to the who-will-be-the-next Israeli prime minister question, don't hold your breath. It could be weeks, perhaps even months, before a new Israeli government is formed – and when it is finally formed, the ultimate winner may not be the party with the most votes.

It sounds strange to American ears (where the drawn out, protracted part of elections happens long before the voting actually starts), but this is an established quirk of the Israeli election system. Israel doesn't have a presidential system like the United States, nor a first-past-the-post parliamentary system like Britain – both of which lend themselves to relatively stable two-party systems.

Instead, Israel uses a party list system of proportional representation. This means that voters go to the polls and vote for a party, and then these parties are assigned seats in the Knesset (Israel's parliament) based upon the percentage of the vote they receive. As of March 2014, any party that receives more than 3.25 percent of the vote can receive a place in the 120-seat chamber.

Proportional representation isn't a system that encourages large parties. Instead, a more fractured political landscapes is the norm, with a greater number of smaller parties. This is pronounced in Israel, where the threshold for gaining a seat is notably lower than many other countries that use a party list system. There are typically at least 10 or so parties operating in the Knesset. At the time of writing, there are 13.

In fact, no single political party has ever won a majority of seats in the Knesset. The closest anyone has ever come was in 1969, when the Alignment Party won 56 seats. Instead, Israeli political leaders have to form coalitions of at least two parties in order to functionally govern. This time will likely be no different – polls released in the Israeli newspaper Yediot Ahronot gave Netanyahu's Likud party a paltry 22 seats, while the Zionist Union (which Herzog's Labor is a part of) was predicted to win just 26. Both would need a coalition to govern.

After today's vote, Israel's president will meet with party leaders and try to work out who has the best chance of forming a government. Usually, the president will ask the party with the most votes to see if they can form a government. The leader of that party will then have around six weeks to form a government. If they fail, the president might ask another party to try, or request that the two largest parties form a unity government.

This can result long periods of uncertainty after elections – and it can also produce some unexpected results. Consider, for example. the case of Tzipi Livni, who became leader of the Kadima party, a centrist off-shoot of Netanyahu's Likud party in 2008. Livni came to lead the party after Israeli Prime Minister Ehud Olmert resigned after a number of corruption probes, yet she was unable to form a working coalition. Livni, a leading advocate for a two-state solution in attempts to settle the conflict with Palestinians, was then compelled to hold an election in 2009. In theory, she won it – Kadima had the most votes of any party and won 28 seats.

But outside of Kadima, the Knesset swung to the right, making it near impossible for Livni to form a government coalition. Ten days after the election, President Shimon Peres eventually asked Netanyahu, whose Likud Party had won 27 seats, to form a government. Livni refused to join a unity government with Likud, and instead opted to enter the opposition. As a testament to the shifting alliances in Israeli politics, Livni later joined Netanyahu's coalition government after the 2013 elections and was then fired by the prime minister in December 2014. She is currently running with Herzog as part of the Zionist Alliance.

The system of political deal-making adds an unpredictable edge to the Israeli elections. Polls may suggest that much of the Israeli public is sick of Netanyahu, but there's no clear successor in place. Instead, it's likely that around a dozen parties will be elected to the Knesset – and smaller parties may end up being unlikely kingmakers. Again, Netanyahu could still win the premiership, even if he loses the election. For now, analysts are divided on what the outcome will be – and whether the resulting government will have any staying power.