By Mick Krever, CNN

In making a case against the oft-repeated argument that Iran is an “existential threat” to Israel, former Mossad chief Efraim Halevy told CNN’s Christiane Amanpour that the country “is indestructible” and should be governed with “self-confidence,” not "memories of the holocaust."

As Iran and world powers negotiate a potential nuclear deal, Halevy says that Israel should be engaged rather than sit on the side-lines.

“I think that Iran is a very serious threat,” Halevy said from Tel Aviv. But “I believe that Israel is indestructible. And I think that this should be the basic tenet of every Israeli leader to have self-confidence, and the confidence in the future of Israel.”

That confidence, he said, “has to be the point of departure” for governing the country.

“It is wrong to bring up the memories of the past, the memories of the holocaust of so many years ago, when we were defenseless,” he said. “Then we were defenseless; now we are not defenseless.”

Halevy was born and spent his early years in the U.K., and he spoke with fondness of Winston Churchill.

“The main theme of everything he had to say, in every presentation he made,” he said, was “that whatever happens, we are confident – we the British people, as it was then – are confident that we will be triumphant. And therefore people should have courage in the courage of their conviction.”

Yes, he admitted, there were serious dangers.

“But there was a strong streak of self-confidence, and I believe that if the prime minister [of Israel] were to take that line, he would be rewarded both in the international arena and inside this country.”

Halevy is outspoken in favor of speaking to Israel’s enemies, including Iran.

“I think it’s always the time to talk,” he said. “The only way to convince people of your views is to talk to them.”

World powers are gearing up for another round of direct negotiations with Iran, after foreign ministers left Geneva last earlier this month without a deal.

Not at the table is Israel; the potential deal is being negotiated by Israel and Germany plus the permanent five members of the U.N. Security Council: China, France, Russia, the UK and U.S.

Halevy called Israel’s absence at the table a “very fateful decision.”

“None of the countries in the region are at the negotiating table,” he said. “The only country at the negotiating table from the Middle East is Iran. There is a price to pay for this.”

Nonetheless, he said, “we have to have a minimum of trust in those who we have asked to represent us.”

This means that the “test of a good deal is the end game; not just the tactics of how your reach the final conclusion.”

Halevy has also advocated negotiating with the Palestinians; despite some road bumps, there are on-going U.S.-brokered talks under way.

Halevy said that a two-state solution was “least probable but most desirable,” while a single state of Palestinians living in an Israel that encompasses Gaza and the West Bank, was “least desirable but the most probable.”

In an interview with Amanpour on Monday, Israeli economy minister and leader of the hawkish Jewish Home party Naftali Bennett denounced the two-state solution.

“I think trying to enforce [an] artificial state in the heart of Israel, in Jerusalem, is a grave mistake,” Bennett said.

“The fallacy in the argumentation of Mister Bennett,” Halevy responded, “is that he believes that this is a game in which we can dictate to the other side the way in which they should live and the way in which they should govern themselves.”

“They are now a nation, for better or for worse. And we are a nation,” he said. “Ultimately we have to negotiate with them from some point of equality.”