JERUSALEM — Israelis like to say that when it comes to military and security operations, those who know don’t talk, and those who talk don’t know. But the intense and increasingly public debate about whether to attack Iran’s nuclear facilities is challenging that piece of conventional wisdom.

The standard view has been that successful attacks rely on secrecy and surprise, so the more talk there is about an operation, the less likely it will occur.

One year ago, Prime Minister Benjamin Netanyahu seemed to support that theory. He told foreign journalists that Iran briefly stopped working on a nuclear weapon only once, in 2003, because that was when the United States attacked Iraq, and Iran feared it might be next.

“The paradox,” Mr. Netanyahu said then, “is that if there is a credible military option, you won’t have to use it.”

In other words, the more noise you make about war, the less likely you will have to resort to it.

But few who have spent time with Israel’s decision makers in recent months have come away believing that the talk of a military assault is merely a well-scripted act of public diplomacy. It is that, to be sure, but there is more. It is also a window into the government’s thinking.

Israel believes that its threats to attack Iran have been the catalyst that has pushed much of the world to agree to harsh sanctions on Iran’s energy and banking sectors, sanctions that otherwise would not have been agreed to. It believes further that the Iranian economy is fragile and the popularity of the Tehran government is low, so that there is a small chance the sanctions could force a change of policy or a political crisis in Iran.

But Israel’s top leaders also worry that the sanctions are too late and that, in the end, a military assault is the only way to accomplish their goal — stopping Iran from obtaining nuclear weapons. So the talk in this crisis is not made instead of action, but in addition to it — and perhaps as a prelude to it.

This was clear again last Thursday evening when the defense minister, Ehud Barak, spoke publicly about what he viewed as the existential nature of the Iranian issue. He said the decisions he and his colleagues faced today were “no less fateful” than those facing the Zionist leaders who founded Israel in 1948 or those just before and during the wars of 1967 and 1973.

“The leader has to decide when to act and when to wait, when and what to declare and when to keep silent,” Mr. Barak told the annual Herzliya Conference devoted to Israel’s security.

He said that never in Israel’s history had a topic of such import been debated with such thoroughness and frankness as this one. An Iran with nuclear weapons, he asserted, would be “far more complex, dangerous and costly in blood and money than stopping it today would be.”

“Those who say ‘later,’ may find that later is too late,” he warned, and added, “We mean what we say.”

Iran says its nuclear program is for civilian purposes only, but the United States, European states and Israel believe that Iran’s goal is to build weapons. Israel is more worried than the others, however, because Iran has singled it out, calling it a “tumor” that should be removed, and the government in Tehran finances and arms violent anti-Israel groups.

Opinions in Israel, however, are far from unanimous on the idea of an assault. The military establishment is unenthusiastic, and that includes several of the most important generals, active and retired. Many reject the conclusion that Mr. Barak and Mr. Netanyahu have embraced, that an Israeli attack would produce only a limited and bearable conflict.

Alex Fishman, a military analyst for the newspaper Yediot Aharonot, wrote on Sunday that a former commander of the air force, Gen. Eitan Ben-Eliahu, likened the situation to the Cuban missile crisis of 1962 when President John F. Kennedy threatened to bomb Cuba if Soviet nuclear missiles were not removed from there.

The Cuban crisis stood on three legs, he said: a naval blockade imposed on Cuba by the United States, military threats and a diplomatic channel of dialogue that allowed the Soviets ultimately to back down. The Iranian crisis, General Ben-Eliahu was quoted as saying, has two of those legs — sanctions and military threats — but it is far from clear that it has the needed diplomatic channel.

The discussion here of an Israeli attack has grown so loud lately that some now worry that it has become counterproductive as a diplomatic tool. Amos Yadlin, a retired general who used to direct military intelligence in Israel, said on the radio on Sunday that it was time to quiet that talk.

“These statements have reached the point where they have crossed the line from bringing benefit and are beginning to cause damage,” he said. “I’ll give you an example. I saw on an Iranian Web site this morning thoughts like, ‘If this is the situation, maybe we should attack first.’ I think there is a danger of escalation that will get out of control. Right now we should do what Israel knows how to do well — keep quiet.”