Jewish organisations in the diaspora have the right to criticise Israel in all respects except one - national security.
So says Daniel Diker, the secretary-general designate of the World Jewish Congress.
"If Prime Minister Netanyahu says an Israeli presence in the Jordan Valley is necessary," Mr Diker said during a recent interview in the WJC's Manhattan headquarters, "then it's a mistake for Jewish organisations to say it's illegitimate or wrong."
Mr Diker's critique comes at a time when the US "pro-Israel, pro-peace" group J-Street is under increasing pressure in the US and in Israel, where the Knesset last week held a hearing into the group.
Though Mr Diker's comments were not directed specifically at J-Street, they came as a warning to the organisation and to other liberal Jewish groups that have loudly criticised Israeli security policy in recent years.
Mr Diker, 50, a former foreign policy analyst at the Jerusalem Centre of Public Affairs, speaks passionately about the complexities of Middle East politics.
He believes the recent wave of Middle East revolutions pose opportunities and threats to Israel. In his view, they also illustrate the importance at Israel retaining parts of the West Bank in order to maintain "defensible borders".
"Every inch of land is vitally important in an environment of profound regional instability," Mr Diker said.
Mr Diker says the Jewish community has the right to criticise Israel on other matters as forcefully as it likes - as long as it chooses its language carefully.
"When you support statements or groups that accuse Israel of being an apartheid state or an 'illegal occupier of Palestinian lands', you begin to endanger Israel's security by undermining its legitimacy," he said.
Mr Diker officially takes over from outgoing WJC secretary-general Michael Schneider in June. But he is already fulfilling many of the secretary-general's tasks, including meeting with Israelis and Palestinians involved in the peace process.
He believes that the Middle East revolutions may prompt a new perspective on the Israeli-Palestinian conflict. "The West made a mistake insisting that the roots of Muslim rage came out of Israel's treatment of the Palestinians. On the streets of Cairo and Tunis, Tripoli and Sanaa, they are not talking about the Palestinian issue. They are talking about their freedom," Mr Diker said.
However, he cautions against pushing Middle Eastern countries into democracy too quickly. "There is a trend in the West for elections as the ultimate flag of Western democracy and to encourage elections as expeditiously as possible," said Mr Diker. "That would be a mistake."