The answer provokes all manner of tortured conspiracy theories about the power of the Israel lobby, the influence of right-wing Christian groups and varied explanations for the gravity-defying trick that enables a tiny tail to wag such a big dog.

Few accept a simpler answer. America supported Israel during the Cold War and built the Jewish state into the most formidable military power in one of the world’s most strategic regions.

While America enjoys strong relations with various Arab regimes, none has come close to matching Israel as a stable democracy and regional superpower.

When America’s direct interests have been threatened by Israeli actions — for instance in the Suez Crisis — Washington has intervened robustly and Israel has backed away.

That is why Israeli leaders need to be particularly careful about how they handle relations with Washington in the current row. Distracted by their own internal politics and accustomed to dealing with two uncritical administrations — Clinton and Bush — the Israelis took Vice-President Biden for granted when he visited Israel last week. Instead of helping him to put in place modest peace proposals with the Palestinians, they announced plans for 1,600 Jewish homes in Arab east Jerusalem.

The Palestinians refused to negotiate under these circumstances and Mr Biden, a strong supporter of Israel, went home humiliated and empty-handed.

This scenario has happened before. But for the first time there are other voices — in this case General David Petraeus, the hugely influential head of US Central Command — openly questioning Israel’s value as a strategic ally. His defining experiences as a soldier, and those of most Americans in uniform, have been Iraq and Afghanistan.

As America becomes more deeply involved in the Arab and Muslim worlds, with nearly 200,000 troops in Iraq, the Gulf and Afghanistan, it will challenge anything that may threaten US lives.

The Pentagon may be coming to the conclusion that the failure to achieve an Arab-Israeli peace deal is the best recruiting sergeant for militant Islam. Live footage of Palestinians being beaten or shot by Israeli troops are beamed around the region on satellite news channels. They can whip up public fury and angry sermons from Cairo to Kabul. America may not be directly involved in these incidents but it is blamed for arming and funding Israel and providing the Jewish state with diplomatic cover at the United Nations. If America’s unwavering support for Israel is endangering the lives of US troops in Kandahar or Baghdad, then the Jewish state has a problem.

Later this week President Obama will return to Indonesia, his childhood home and the world’s most populous Muslim country. This should be an occasion when he can reach out to the Islamic world and heal the wounds caused by the September 11, 2001, attacks. For that he needs to know that his ally Israel is willing to help make that job easier, not harder.

Source > TIMES online