A bit more than three years after Mr Meir Dagan was forced to end his long tenure as director of Israel's intelligence service Mossad, he showed up at a discussion on the Middle East filled with contempt for Israeli Prime Minister Benjamin Netanyahu who, he feared, was on the cusp of bombing Iran's nuclear facilities.

"There is no one to stop him anymore," Mr Dagan told me at Harvard University in the spring of 2014.

Mr Dagan had long argued that by pushing him and other intelligence and military leaders out of office, Mr Netanyahu was seeking to silence those who pointed out that there were better ways to deter Iran from getting the bomb than by attacking the country's facilities.

At best, Mr Dagan said at Harvard, an Israeli bombing run would provide an illusory solution, temporarily flattening those facilities, only to see them return, this time deep underground. The result, the spymaster and former soldier argued, would be disastrous for Israel.

Mr Dagan, who died on March 17 after struggling for several years with a liver transplant that never quite succeeded, could hardly be accused of being soft on Israel's enemies. He ranked among the most brutal warriors of the modern Middle East. He famously kept a photograph of his grandfather, kneeling on the ground before his Nazi captors moments before he was killed. Mr Dagan would show it to visitors, a personal "never again" memento that seemed to explain the ease with which he organised the elimination of Israel's enemies.

Short, bald and built like a fireplug, Mr Dagan was unquestionably capable of enormous brutality: During his military career, he led squads that killed Palestinian militants. Mr Ariel Sharon, the late former Israeli prime minister who had been his mentor and commander, once said: "Dagan's specialty is separating an Arab from his head."

Later, many suspected Mr Dagan's hand in the killing of Iranian scientists, who would be driving to work in Teheran traffic only to have a motorcyclist pull up and attach a "sticky bomb" to their cars' doors before speeding off. Eventually, the succession of such killings became so obvious that then US Secretary of State Hillary Clinton felt compelled to condemn them in public. Mr Dagan never discussed those missions.

It was Mr Dagan who managed Israel's side of perhaps the most sophisticated piece of sabotage the US and Israel ever jointly attempted: the years-long cyber attacks meant to destroy Iran's nuclear centrifuges.

Mr Dagan was no computer hacker, but he appreciated technology that made it enormously difficult for the Iranians to figure out the origin of the attack. To his mind, the operation - elaborately planned with two American presidents - showed how Israel should defend itself in the future: not with open demonstrations of military might that invited retaliation, escalation and condemnation; not with assassinations and occupations; but with subtlety and indirection.

At a cocktail reception during another conference, Mr Dagan sought me out to criticise a lengthy account I had written, in The New York Times and in a book, about the cyber attacks. I was surprised to discover that he was not worried about the revelation of a highly classified intelligence operation, only that Israel - and more specifically, the Mossad - had not been given enough credit.

"You missed a major part of the story," he said, arguing that the Americans had received far too much credit for an operation that he believed the Mossad and Unit 8200, the famed military intelligence group, made possible.

If Mr Dagan wanted to tell Israel's side of the story, I suggested, I would certainly write more about it.

He squinted at me, then laughed. "I am an old man," he said, "and I am sick. I don't want to spend my last days in jail."

Mr Dagan was always careful. He offered no operational details. In our handful of conversations over the years, he sprinkled phrases like "if we did it" into many sentences, so that he could explain his underlying logic without violating his oath to maintain the secrecy around the Mossad's covert operations.

But in retrospect, in his war with Mr Netanyahu, which escalated through the Prime Minister's re-election a year ago, Mr Dagan appeared to have two main objectives. The most likely was restoring his own reputation after an embarrassing failure of basic tradecraft, when Mossad agents were caught on tape entering and leaving a hotel in Dubai during the 2010 killing of a senior official in the Islamist Palestinian group Hamas. The success of the cyber attacks in slowing Iran's nuclear programme could be critical to his legacy, but that did him no good if the world thought they were Washington's work.

But Mr Dagan may have had another reason, more political and only slightly less self-interested. It was part of his effort at restraining Mr Netanyahu and Mr Ehud Barak, the other leading advocate of an Israeli bombing campaign against Iran's nuclear facilities.

Mr Dagan, like many US officials, believed that at least some public revelation about the cyber attacks would show there was a more elegant, less provocative way to set back the Iranian nuclear programme, making it more difficult for Mr Netanyahu and Mr Barak to scramble the fighter jets.

When he left office in 2011, Mr Dagan told the Israeli Parliament that "technological difficulties" would delay Iran from building a bomb until at least 2015. (It turned out that was the year that, over Mr Netanyahu's strenuous objections, Iran and a group of six nations led by the United States reached an agreement that, on paper at least, prevents the Iranians from making the fuel needed for a bomb for another 10 or 15 years.)

But that was not the message Mr Netanyahu wanted broadcast. So in the last years of his life, Mr Dagan engaged in open battle with the government he once served. As he accelerated his critique of the military-attack option, his diplomatic passport was pulled. Mr Barak, the former prime minister turned defence minister, told Israel Radio that Mr Dagan was harming "Israel's ability to deter" the Iranians.

Mr Dagan, though, argued that Iran was a deeply divided political entity, and an open conflict with Israel would only help unify its feuding parties. "Go directly against the regime itself," he told me once, explaining his strategy. "There is real division there."

It is impossible to say what role the public campaign against a military strike by Mr Dagan and other former Israeli security leaders played in Mr Netanyahu's decision not to pull the trigger.

But there is no doubt that by the time he was buried last week, Mr Dagan had won his argument, at least for a while.

The Iran nuclear deal had silenced the calls for military attack; after the Iranians shipped 98 per cent of their fuel out of the country, it could hardly be justified.

And in the past two months, as Mr Dagan lay dying, some Israeli leaders began to concede that the US approach bought them more time than any military strike ever could.

NEW YORK TIMES