In a shocking development, Israel’s Knesset today voted to dissolve itself and call for new elections, after Benjamin Netanyahu failed to form a governing coalition. The contest is scheduled for September 17.Wait, back up: how did this happen?Israel’s parliament contains 120 seats, which meant Netanyahu needed 61 to form a government. He got to 60 before he was stymied by Avigdor Lieberman, head of the hard-right Yisrael Beitenu party, and an old personal nemesis, who used a popular wedge issue to blow everything up.Though Yisrael Beitenu is right-wing in orientation towards the Israeli-Palestinian conflict, it has long had another crucial domestic orientation: anti-clerical and anti-ultra-Orthodox. This is because the party’s base is comprised of secular Russian voters who immigrated to Israel from the Soviet Union, many of whom have had their Jewishness questioned by Israel’s ultra-Orthodox Chief Rabbinate. For over a decade, Lieberman and his party have sought to undermine the political power of the ultra-Orthodox, and have pushed a bill to compel the community to be drafted into the Israeli army, from which they currently enjoy an exemption.This is a popular position in Israeli politics, but because Netanyahu has needed the ultra-Orthodox parties to maintain power, it has been perpetually pushed off the agenda. This time around, however, Lieberman refused to compromise, and withheld his party’s five Knesset seats from Netanyahu unless he caved, effectively dooming his coalition prospects.Some commentators suggest that Lieberman, who got his start in politics as an aide to Netanyahu but has since become his bitter foe, was simply using this wedge issue to exact political revenge against Bibi. But regardless of Lieberman’s true motivation, the outcome is the same: Israel will be heading back to the polls on September 17, and re-running the election campaign they concluded just seven weeks ago.What makes this election any different than the last one?Given that Israeli voters just expressed their preferences, some doubt that another round of elections will conclude any differently. And it is certainly most likely that the next campaign will turn out the same as the last one. But there are five important factors that could still change the calculus:1. Will settler leaders Naftali Bennett and Ayelet Shaked run again, and with whom? Last election, the charismatic duo of Bennett and Shaked broke off from Israel’s religious settler party to form their own “New Right” party. They ran on a message of religious-secular unity (Bennett is modern Orthodox, Shaked is secular) and promised to annex the West Bank and to subordinate Israel’s Supreme Court to its parliament. Shockingly, these two hard-right mainstays of Israeli politics fell just short of enough votes to enter the Knesset and their party was washed out. In the process, they wasted tens of thousands of right-wing votes. The question now becomes: will their party run again, risking the same outcome in the hopes of crossing the Knesset threshold? Or will they attempt to rejoin other parties and run with them? Shaked, in particular, has been courted by several right-wing parties, including Netanyahu’s Likud. (Bennett, by contrast, fell out with Netanyahu years ago much like Lieberman, and would have a tough time linking up with him.) How this plays out could determine the fate of scores of right-wing votes.2. Will the Arab vote grow? Prior to April’s election, Israel’s Arab super-party, The Joint List, broke up into several different parties. Two of them made the Knesset, one did not. Overall, the maneuver both decreased Arab turnout at the polls and decreased Arab representation in parliament. Whereas the Joint List commanded 13 seats in the old Knesset, the new one was slated to have just 10 Arab seats, divided among the Hadash-Ta’al and Ra’am factions. This outcome was a big reason why the Arab parties voted today to go to new elections: they hope to reform their super-party and drive up turnout again. Doing so could add several seats to the Knesset’s anti-Netanyahu caucus, and could block his pathway to a coalition.3. Will Likud’s merger with the center-right Kulanu party help or hurt Netanyahu’s prospects? In a last-ditch attempt to signal strength and head off new elections, Netanyahu merged his Likud party on Tuesday with Moshe Kahlon’s center-right Kulanu party and its 4 seats. Technically, this math would predict that Bibi get 39 seats in the next Knesset. But that is not always how these right-wing mergers turn out. Back in 2012, Netanyahu merged his Likud (27 seats) with Lieberman’s Yisrael Beitenu (15 seats) to form a Likud-Beitenu juggernaut, but while the two had 42 seats standing separately in the previous Knesset, they got only 31 together in the 2013 elections. If Kahlon’s soft-right voters similarly desert Likud–after all, they refused to vote for Netanyahu in April–and defect to the chief Israeli opposition Blue & White party, which spent much of its campaign trying to woo them, it could tip the balance in the Knesset away from Netanyahu. But if these voters stick with Kahlon under Bibi, they could ensure the latter’s return to power.4. Will ultra-Orthodox enlistment in the army dominate the election agenda? As Lieberman understood and demonstrated this week, the popular movement to end the ultra-Orthodox exemption from military service is the chief pressure point for Netanyahu’s traditional political coalition. Without the ultra-Orthodox, it is hard for him to form a government, but his repeated concessions to their political demands have been tremendously unpopular with the Israeli public, from left to right. The more this sore spot is poked, the more Netanyahu is put in an impossible position. If the new election is framed around this issue, and opposition parties stake out more popular terrain on it, Netanyahu will be forced into conflict with either the broader public or his ultra-Orthodox partners, putting him under serious pressure throughout.5. Will the new election finally be the tipping point for Bibi fatigue? The last election was run as a referendum on Bibi, and turned on whether or not enough voters–including on the right–would reject the perennially unpopular Likud leader, whose double-talk, corruption scandals, and family soap opera have soured many constituents on him. Netanyahu countered by casting himself as Israel’s indispensable man, a steady statesman at the tiller upon whom Israelis could rely to responsibly govern their affairs, unlike his untested opposition. But after Bibi proved unable to even form a coalition among a sea of like-minded lawmakers, will enough voters buy that argument again this time, especially as new evidence continues to leak from his ongoing corruption cases?Betting against Netanyahu in Israeli politics is like betting against Tom Brady in the Super Bowl, and he is still the favorite to win this next round. But he also just took an unprecedented body blow, one suffered by no other Israeli politician in history. He could emerge stronger than ever, if voters rally to ensure he gets a more decisive mandate, or he could be hobbled by the perception that he is a weakened leader on the political ropes. Speed bump or sea change? Israeli voters will decide.