For skeptics who doubt a peace deal between the Israelis and Palestinians is still possible, former Israeli Prime Minister Ehud Olmert argued passionately this week that now is the moment — and his plan is the answer.

Olmert’s plan, which is the most far-reaching offer ever made by an Israeli leader, isn’t new. It was presented to Palestinian leader Mahmoud Abbas in September 2008, when Olmert was in office. Abbas famously never rejected it, but never said “yes.”

Yet, at a moment when Secretary of State John Kerry is struggling to revive peace talks, Olmert’s plan remains the most realistic, one that Kerry should be promoting. You can doubt its chances, but Olmert made a compelling case for why, despite the current Mideast chaos, Israel urgently needs a peace deal, now.

The former Israeli leader provides a fascinating study in contrasts: a longtime conservative mayor of Jerusalem who came to believe the city must be shared between Israelis and Palestinians; a member of the hawkish Likud Party who became convinced as prime minister, from 2006 to 2009, that a two-state solution was essential for maintaining a democratic Jewish state.

I’ll get to Olmert’s plan in a moment, but what’s equally interesting is his case for why the need for a deal is so urgent, and the security risks so manageable. Speaking at the Woodrow Wilson Center in Washington on Tuesday, he rebuffed the claim that today’s Middle East is too unstable for Israel to give back territory to the Palestinians.

“There never was a time in which Israel was [in] better security shape than we are now,” he insisted. Neither Syria’s Bashar al-Assad, nor anyone who follows him, will have the power or resources to fight with Israel for the foreseeable future, he said.

Egypt’s elected Muslim Brotherhood leaders, facing “the responsibilities of feeding 80 million people,” can’t indulge in military adventures. Hezbollah has been cowed from sending rockets into Israel since its war with Israel in 2006. Iran is a real threat, but one where Israel has international support.

As for the risk that a Palestinian state would become a base for rocket fire on Israel — as happened when Israel withdrew from Gaza — Olmert admitted terrorism would remain a danger but said “Israel can deal with it.”

He pointed out that the Gaza withdrawal was unilateral, while any Palestinian state would be established by a treaty that would be backed by the United Nations, all world powers, and Israel’s Arab neighbors. This would give Israel a full legal right to respond forcefully to any future violation of its sovereignty. The Palestinians would be fully aware of this.

But why did Olmert see such an urgent need for a treaty? Olmert fears that, absent a peace treaty, future Palestinian leaders may not be as moderate as Abbas. He also fears that continued occupation will lead to the international isolation of Israel.

In such circumstances, Palestinians may give up on two states and demand one state with equal voting rights for Palestinians. To grant this demand would mean the end of the Jewish state. To refuse it would mean an end to Israeli democracy, with Palestinians deprived of human and political rights.

The West Bank calm that Israelis have been enjoying will not last.

Which brings me to Olmert’s plan for a two-state solution: A Palestinian state would be established on land equivalent in size to the pre-1967 West Bank and Gaza, with agreed-on land swaps to compensate Palestinians for Israel’s annexation of some Jewish settlement blocs. Jerusalem’s Arab neighborhoods would be the capital of the Palestinians state, while the holy places would be administered jointly with the help of Jordan, Saudi Arabia, and the United States. The Palestinian refugee problem would be settled by mutual agreement, with only a small number allowed into Israel and most going to Palestine.

Olmert rightly believes that Palestinian leaders can’t accept less than the parameters he offered. However, current Israeli Prime Minister Benjamin Netanyahu rejects the plan’s proposal on borders and on Jerusalem. Abbas, while waxing positive in private, has never endorsed the plan in public.

For peace efforts to have a chance, argued Olmert, they would require “the more active support of the president [Obama], just as [George W.] Bush did and President Clinton did.” He noted that both ex-presidents were actively involved in peace-process details (something Obama has studiously avoided).

I’d argue that Obama should also promote the Olmert parameters, urging both Netanyahu and Abbas to endorse them, since they hold the most realistic prospects for a peace deal. Short of that, administration rhetoric about the peace process amounts to little more than well-intentioned hot air.