An Israeli academic and former politician predicted this week that the twin demographic rises of the Muslim and Haredi communities in Israel "could lead to a secular flight from the country".
Professor Amnon Rubinstein, a former minister of education and of communications, and a professor of constitutional law, described himself as "full of anxieties" about the future of the Jewish state.
In an interview to mark the publication of his latest book, Israel and the Family of Nations - the Jewish Nation-State and human rights, Professor Rubinstein said: "We have a situation in Israel in which the demographic trend favours the Muslim and Haredi minorities. They have one thing in common: they don't serve in the army, they don't accept the Declaration of Independence, or the national symbols of Israel, or Holocaust Memorial Day, and most of all, they don't participate in the civilian work force. If these trends continue, they may bring about a secular flight from Israel."
But Professor Rubinstein was, nevertheless, hopeful that "a certain part" of the Muslim and Haredi communities could be integrated into mainstream Israeli society.
"Israeli Arabs would have to chip in and do some sort of civil service for the community," he said. "We must have an opening for the possibility of young Muslims volunteering for the Israeli army, and becoming part of the young society of Tel Aviv and Jerusalem".
However, he expressed major concern about the external threats to Israel - "the Muslim world has still not acquiesced in the idea of a Jewish state" - and what he called the "continuous movement to delegitimise Israel," which, he said, "would have the effect of further isolating Israel from the world to which it naturally belongs - the democratic family of nations."
His book, written with legal researcher Dr Alexander Yakobson, is, he said, "very unfashionable. But these days I am like Rhett Butler in Gone With the Wind. Frankly, I don't give a damn." The book is a robust rebuttal of the "post-Zionist" school of thought. "There is a new, post-modern relative point of view, where everything is subjective and the Palestinian narrative is equal to the Jewish narrative. Well, guess what? There was a Nazi narrative. Is that, too, equal?"
Part of the book is devoted to a detailed discussion of Israel's Law of Return, formulated by David Ben-Gurion in order to anticipate potential waves of Jewish immigration. These days, Professor Rubinstein believes, there is a need for an immigration law.
"I headed a Commission on Immigration Policy three years ago in which we recommended the introduction of an immigration law which would take account of the large number of people coming to Israel who are not Jewish - foreign workers, people who are not halachically Jewish. The attempt failed but de facto, there is non-Jewish immigration to Israel and we need to take account of that."
Currently provost and dean of the school of law at the Interdisciplinary Centre (IDC) in Herzliya, Professor Rubinstein is an optimistic supporter of the voice of the Jewish diaspora. Israel, he asserts, "should be a Jewish state for all its potential citizens."