Moments after exit polls confirmed his surprise second-place showing in Israel’s January 22 parliamentary elections, political neophyte Yair Lapid faced his giddy supporters and declared: “A serious responsibility has been placed on our shoulders tonight.”

That’s for sure. With left and right exactly tied at 60 seats each in the 120-seat parliament (with 99.8% of votes counted at press time), Lapid essentially gets to decide who will be Israel’s next prime minister.

He can bring his 19-member caucus of moderate liberals across the aisle to prop up the staunchly conservative incumbent Benjamin Netanyahu, who came in first with 31 seats but lost his old majority. Or he can join with his fellow liberals, former foreign minister Tzipi Livni and Labor Party leader Shelly Yachimovich, to form a new majority, presumably after wooing over a few defectors from the right. Either option is perfectly legal. Both entail betraying one or more of his core principles. It’s all up to Lapid.

It won’t be easy. A hugely popular television anchor and newspaper columnist, Lapid jumped into politics a year ago to clean things up. He considers himself a devout centrist, committed to rising above politics-as-usual and creating a government “that unites the moderate forces on left and right,” as he put it election night.

His first instinct is to give the baton democratically to first-place winner Netanyahu. The two began discussing a partnership as soon as exit polls came in, according to published reports. But joining Netanyahu might prove impossible, due to complicated mathematics and a gulf in core values. It’s going to get messy.

In the end, Lapid is likely to find himself in the same position as another political naïf who entered national politics not so long ago with hopes of rising above politics as usual. I’m talking about Barack Obama. Lapid’s problem, like Obama’s, is that the divisions are real. The game gets ugly because the stakes are so high. Like Obama, Lapid will find that the moderate center he wants to assemble simply doesn’t exist within today’s legislature.

Lapid’s rude awakening will arrive a lot quicker than Obama’s. Within 77 days, to be exact. That’s how long Israel’s quasi-constitutional basic law allows, from the moment the vote results are officially published, for a would-be prime minister to negotiate with other parties, forge a viable coalition and win a Knesset vote of confidence.

Here’s how it works: Israel’s ceremonial president, 89-year-old liberal icon Shimon Peres, has seven days to consult with all the parties, hear their recommendations for prime minister and then tap the likeliest contender. Peres’s choice gets 42 days to craft a coalition. If he or she fails, the president can pick someone else, who then has 28 days to try. Failing that, the Knesset is dissolved and new elections follow. With the blocs tied 60-60 and the sides more polarized than ever, that’s not inconceivable.

Netanyahu wants Lapid to join him in a centrist bloc, united behind Lapid’s signature cause of ending draft deferments for ultra-Orthodox yeshiva students. Between them they have 50 seats. They aim to join forces with the other new star of this election, high-tech entrepreneur Naftali Bennett of the pro-settler Jewish Home party, who agrees on ending the yeshiva deferment. Now they total 61. Add in the two seats of the once-mighty Kadima and they get to 63. Shaky, but it’s a start. They disagree on Palestinian statehood, but Lapid figures that can be put on the back burner.