The unveiling of Donald Trump’s “deal-of-a-century” peace plan for Israel and the Palestinians has been postponed yet again, probably at least until after next month’s Israeli election.

Few diplomatic initiatives have been saddled with such low expectations, but the president will believe he can confound them and succeed where his predecessors failed.

In the meantime, the emboldened Israeli right believes the two-state solution, once regarded as the cornerstone of any peace agreement, has been consigned to history. But if the two-state plan is no longer on the cards, what realistically could take its place?

The old Jordanian option surely remains a non-starter. Perhaps somewhere down the line waits a coalition of Sunni states which could be persuaded to assume responsibility for the rump of the West Bank and Gaza, though that scenario would still likely involve some nominal Palestinian state.

So for those who dismiss the two-state deal, what “alternative arrangements” are there?

Here let me bring in Tal Keinan, the American-Israeli businessman and former F-16 pilot in the Israeli Air Force, whom we featured in our Judaism section last week. His book God Is In The Crowd is foremost a call for action to save the Jewish people, in the wake of his fears about the assimilation of the mass of American Jewry and Israeli Jewry's fissiparous religious-social divisions.

This is what he writes about the Israeli-Palestinian conflict. There are, he says, “only three possible endgames”.

The first is that Israel could annex the West Bank and give its Arab residents citizenship – which would mean Israel “opening itself to the prospect of demographic suicide”. Democracy and demography would ultimately “reduce the Jews of Israel to another minority in the Middle East”.

The second option would be to annex the Palestinian territories without granting the Palestinians citizenship – imposing sovereignty on a large number of people without representation. But he argues: “Most Israelis that I know would find their very loyalty to the state undermined if Israel ceased to be a democracy. Many would immediately seek to establish their lives elsewhere.”

As Israel’s “best and brightest” left, the economy would falter and the state could become isolated and eventually unviable. “Like the first, this option is likely to represent the end of Israel as we know it.”

The final option – he says he has sought a fourth but “never found it - is for Israel to withdraw from most of the territories, with or without an agreement with the Palestinians. If the Palestinians build a state, there will be a state, but if not, the West Bank “will likely become another rocket base”.

Maintaining Israeli security would be difficult in those circumstances, he recognises, but adds: “Facing a sovereign country instead of an occupied territory, Israel could be far more aggressive in defending itself than it currently it is.”

His conclusions are stark. “Israel is not likely to survive if the Jews become a minority. It is not likely to survive as an undemocratic state. This leaves only one option.”