What the Iran deal means for Israel is a matter of debate: Proponents of the deal say it will keep Israel safe from Iran ever getting a nuclear bomb, whereas critics worry that the deal could fail, and that even if it doesn't it will distract from Iran's non-nuclear aggression. It is, and will continue to be, a legitimate and important policy debate.

But even if the deal does end up being good on net for Israel, there is just no debating that it is a complete disaster for Israeli Prime Minister Benjamin Netanyahu.

This deal is a huge policy failure for Netanyahu, who in recent years has staked ever more of his legacy and political reputation on stopping it — even at the cost of setting back Israel's relationship with the United States. Now he has nothing to show for it but a giant political embarrassment that his opponents on the right and left are already using against him.

The Iran deal is a massive policy defeat

Netanyahu has made confronting Iran central to not just his agenda but his very political identity. He's been sounding the alarm about the threat to Israel from an Iranian bomb since at least 1992. His warnings have been beyond bombastic: Iran is a "genocidal" enemy akin to the Nazi regime, its leadership a "messianic apocalyptic cult" that wants to "take over the world."

Everything we know about Netanyahu's beliefs and background suggests that even if his language is overstated, his fears about Iran are genuine. Obama's Iran deal, he worries, guarantees that these warnings will come to pass.

"The concessions agreement Iran is about to receive from the world powers paves its way to acquiring nuclear weapons," Netanyahu said just a week before the deal.

He was even blunter in February: "The agreement being formed between Iran and the powers can endanger our existence." (Israel's military brass and top intelligence officials disagree, according to the Economist).

So Netanyahu pledged to do "everything I can" to stop a deal from being made. And indeed he did, most (in)famously by delivering an anti-deal speech in front of the US Congress — a speech orchestrated behind Obama's back, and at some cost to the US-Israel relationship.

Netanyahu's Iran policy has become a disaster, a boondoggle, a total belly flop

He failed. He's now trying to rally Congress to kill the deal, but it's very unlikely he'll succeed. It'll be tough for the next president after Obama to kill the deal unilaterally even if he or she wants to. And Israel doesn't have much in the way of good military options without American cooperation, which it certainly wouldn't get now (assuming the deal holds).

It's hard to overstate how much of a defeat this is for Netanyahu. He lost the policy fight on his top issue. It would not be too far off to imagine this as akin to Obama losing the 2010 vote on Obamacare, if Obama had insisted that without Obamacare, America itself faced imminent destruction.

Netanyahu's Iran policy has become a disaster, a boondoggle, a total belly flop. His top priority was blocking a deal, and he couldn't get it done.

This failure is going to be a political liability

Netanyahu is hardly the only Israeli skeptical of a deal: 69 percent of Israelis polled by Channel 10 news opposed it.

Israelis are much more divided, by contrast, on Netanyahu's performance. Thirty-seven percent said the prime minister "had made mistakes" in his handling of the nuclear deal, 34 percent said his approach was "about right," and 29 percent said they did not know.

Netanyahu's opposition sees an opening; some opposition leaders on his left are already hitting him.

"We stand today facing the greatest foreign policy failure by any Israeli prime minister since the establishment of the state," Yair Lapid, head of the centrist Yesh Atid party, said Wednesday. "[Netanyahu] needs to go home after a failure of such colossal proportions. The prime minister cannot remain in office."

Isaac Herzog, chief of the leading opposition party Labor, is behaving curiously. Initially, he called the deal a "clear failure" of Netanyahu's policy. Now he's meeting with Netanyahu to discuss strategy for opposing it. The Israeli press is reporting rumors that he might be about to join Netanyahu's coalition, as foreign minister, to help the last-ditch effort to torpedo it.

"The prime minister cannot remain in office"

But expect the knives to come out at election time. Netanyahu's coalition was already tenuous, and this could eventually create an opening for opponents on both his right and his left. Every party on the Israeli political spectrum has an incentive to attack Netanyahu on the Iran deal, given how much the Israeli public cares and how resounding Netanyahu's failure is.

This will likely remain the case even if Israelis warm up to the deal. If the deal is a disaster, Netanyahu's opponents can blame him for failing to stop it. If it turns out well, and Israeli public opinion shifts, they can blast Netanyahu for throwing Israel's relationship with America under the bus for no reason.

Either way, Netanyahu's position on what has been one of his most central issues is severely weakened. The Iran deal isn't just a substantive defeat for Netanyahu — it's a political catastrophe.