Last week brought significant and dramatic developments to Israeli politics. As the deadline to submit final lists approached, four consequential electoral mergers came to life:

On the right, Otzma Yehudit, a far-right party founded by acolytes of Rabbi Meir Kahane, joined forces with Bayit Yehudi, the flagship party of religious Zionists formerly led by Naftali Bennett, and Tkuma, another religious Zionist party headed by controversial MK Bezalel Smotrich.

In the center, the announcement of a historic alliance between Benny Gantz’s Hosen Leyisrael, which had already fused its list with Moshe Ya’alon’s Telem Party, and Yair Lapid’s Yesh Atid offered renewed hope for Israelis desperate to see the end of the Netanyahu era (not to mention their sympathizers abroad).

Among the parties that previously made up the Joint List, two alliances formed: Hadash and Ta’al, the parties led by Ayman Odeh and Ahmad Tibi, respectively, agreed to combine their parties. Polling indicates this list will win definitely cross the electoral threshold with around seven-to-nine Knesset seats. Forming a less secure partnership was Arab nationalist Balad, which had been hobbled by the sudden retirement of its two most prominent MKs, Jamal Zahalka and Haneen Zoabi, and Ra’am (United Arab List), which in previous years ran with Ta’al.

However, the Zionist left experienced no such unity. Despite attempts to reach an agreement in the final hours, Labor and Meretz failed to do so. This failure to merge, which appears to have been the choice of Labor, was an unnecessary blow to the broad opposition bloc, which is now led by the Gantz-Lapid list Kachol Lavan.

In the scope of recent Israeli political history, Labor and Meretz are not the natural partners they may appear to be to outside observers. Every Labor leader since Amir Peretz lost the 2007 leadership race has concluded that the party’s left-leaning image is an albatross in its path back to power. They mainly tried to obscure this by either running to the right on security-diplomatic issues or downplaying them altogether, effectively ceding the most important issue in Israeli politics to their opponents. Meretz, in response, has explicitly run as “the Left of Israel.”

There, is of course, credence to claim that Labor can’t lead a coalition as a left-wing party. The “left” brand has suffered terribly in the last 20 years, a result of both the Second Intifada and years of political demonization by the right-wing parties, especially Likud. According to a recent comprehensive survey conducted by the Israel Democracy Institute, only 23 percent of secular Israeli Jews are even willing to call themselves center-left or leftist (10 percent and 13 percent, respectively). The numbers for every other Jewish group in Israeli society are much lower. The political scientist and pollster Dahila Scheindlin puts the overall percentage of Israeli Jews who are leftists at a decrepit 15 percent.

But there is little evidence Labor fairs much better as a centrist party or one that arduously avoids being labeled as leftist. While it’s true a centrist is more likely to beat Likud, there is no reason to believe Labor could be that centrist party given its historical baggage, left-leaning support base, and the availability of bona fide centrist alternatives. Shelly Yachimovich, who led the party into the 2013 elections with a campaign that hardly touched on security and diplomacy, knows this better than most. Perhaps that’s why she pushed hard for a merger this week, one of a series of entreaties that Gabbay ultimately ignored.

Gabbay’s reasoning that Labor is stronger alone and Meretz will cross the electoral threshold on its own crumbles when presented with data. While Labor appears secure but beaten at 7 to 10 seats, Meretz has not polled above 5 mandates in recent weeks; in fact, they’re often times at 4 and treading on the electoral threshold. The risk of Meretz being “erased,” as Yachimovich put it, is a prospect very much worth dwelling on – especially when you consider the effect of center-left votes being drawn to Gantz and Lapid. In 2009, when it was clear Tzipi Livni was the only candidate competing with Netanyahu for the chance to form a government, Meretz received 2.95 percent of the vote, its worst performance and one that would not permit it enter the under the current threshold Knesset on April 9. While the surplus vote agreement the parties eventually concluded modestly reduces the risk of Meretz disappearing, that is contingent on the surplus votes of Labor being enough to put Meretz over the threshold.

By running together, Labor and Meretz had a chance to consolidate the modest strength of the Zionist left, and perhaps even win over some Arab voters frustrated by the infighting among former Joint List parties. Given the attraction of Gantz and Lapid, it would not have amounted to much — perhaps a group of 12-14 mandates, but a respectable number that would’ve provided leverage in the event of coalition negotiations with Gantz and Lapid. Now, in the best case scenario, both parties will make it into the Knesset with such a combined strength but without the benefit of negotiating as an indivisible bloc. Unfortunately, there is now the possibility of losing Meretz altogether, and with it four seats, which the opposition absolutely cannot afford.