A funny thing happened during the Israeli government's most recent rhetoric bombing of Iran. Shimon Peres, Israel's 89-year-old president, pushed back. Mildly, yes, but publicly.

Why did Peres, whose position is basically ceremonial, feel the need to counter the government's lock-step, we'll-go-it-alone march to war? Perhaps because the veteran politician sensed a dangerous trend at play: Prime Minister Benjamin Netanyahu's radical government is becoming a real threat to Israel's long-term relationship with the US.

A special relationship

The alliance between the US and Israel needs little introduction. The two countries share strong cultural, political and historical bonds, which their leaders trumpet at every opportunity. When Netanyahu addressed the US Congress in May 2011 he got 29 standing ovations – that's more than President Obama got during his 2011 State of the Union speech.

But Netanyahu's apparent popularity in the US Congress and largely unchallenged leadership in Israel mask real fissures. Many of Israel's liberal-minded supporters in the US are deeply uncomfortable with its harsh policies on the occupation of the West Bank (not to mention Netanyahu's attacks on Israel's own democratic institutions). In 2008 J Street emerged as a more progressive and peace-oriented alternative to Israel's more bellicose advocates in Washington.

Then, in 2010, US journalist Peter Beinart published a groundbreaking and controversial article in the New York Review of Books called "The Failure of the American Jewish Establishment". Beinart's argument was simple: unlike their conservative peers, young secular Jews in America felt less attachment to Israel and reserved the right to apply a liberal, rights-based critique to the country. He wrote:

Morally, American Zionism is in a downward spiral. If the leaders of groups like AIPAC and the Conference of Presidents of Major American Jewish Organizations do not change course, they will wake up one day to find a younger, Orthodox-dominated, Zionist leadership whose naked hostility to Arabs and Palestinians scares even them, and a mass of secular American Jews who range from apathetic to appalled.

The essay was applauded and attacked (in a sense confirming its argument); in 2012 Beinart followed it with a book called The Crisis of Zionism.

With friends like these ...

This tension, decades in the making, has become more political under Netanyahu's premiership and Barack Obama's presidency. By all accounts the relationship has been frosty. Obama's calls for a halt to Israeli settlement in the West Bank were largely ignored by Netanyahu, and the Israeli PM openly opposed Obama when he called for a peace agreement with Palestinians based on 1967 borders.

Now, months before Obama stands for re-election, Netanyahu has spearheaded a new media campaign detailing Israel's supposed need to attack Iran. The legitimacy (or illegitimacy) of that claim aside, many see the push as an attempt to corner Obama into pre-election promises, in order to safeguard the Jewish vote. Add to that Netanyahu's clear preference for Obama's opponent, Mitt Romney: an old friend who, in essence, has promised to farm out his Middle East policy to the Israeli right.

And here's the rub

It's not difficult to see where the danger lies in this strategy. Netanyahu has adopted many of the policies that American supporters of Israel find most troubling: colonisation of East Jerusalem and the West Bank, more laws that discriminate against Palestinian citizens of Israel and, more generally, fostering a culture of hate.

Moreover, he appears to be embedding himself in a red-hot US electoral cycle that highlights issues far more pressing to most Americans than the needs of Israel. And he looks to be picking a side – one that many secular supporters of Israel vehemently oppose. Perhaps that is why President Peres came out and said he trusts Obama as a gesture of goodwill to concerned American supporters.

But the question remains: how long can Netanyahu challenge Obama and cast off liberal American supporters before he threatens the heart of this special relationship?

Learn more: Read David Shulman's incisive review of Peter Beinart's The Crisis of Zionism for the New York Review of Books.