There have been many watershed moments in the evolution of America’s Middle East policy. In 1945, President Roosevelt met Saudi Arabia’s King Abdulaziz bin Abdulrahman Al-Saud in Egypt to forge a partnership based on economics. Voting for the creation of Israel in 1947 established its companion: an unshakeable connection between the US and the Jewish state driven principally by domestic electoral considerations. In 1956, Washington condemned France and Britain for conspiring with Israel to recover the Suez Canal and became the dominant power in the Middle East. Arab-Israel wars in 1967 and 1973 forced Washington into the role of peacemaker. In 1979, Iran replaced the Soviet Union in America’s mind as the principal threat to US interests in the Middle East. In 1990, America intervened militarily to defend the status quo. Thirteen years later it invaded Iraq to change it.

The spring of 2011 is emerging as another watershed moment. It is too soon to say how significant it will be. But there are already signs it could be momentous.

The forced resignation of Zine el-Abidine Ben Ali and Hosni Mubarak as heads of state of Tunisia and Egypt respectively were unsurprising events. Both were old men who refused to recognise it was time to give up power and go. Demonstrations in Bahrain reflected long-term discontent. Libya’s Muammar Qaddafi had created a system without the capacity to cope with his departure. There was always going to be chaos when his time to retire came.

These were not shocks, although their timing and character could not have been accurately forecast. The development that was came from the White House. Almost immediately after anti-government demonstrations started in Egypt, America signalled it wanted Mubarak to go without delay. Even a demand from Saudi Arabia’s King Abdullah bin Abdulaziz al-Saud that the Egyptian president should be allowed to leave in dignity was ignored. On 11 February, soon after Mubarak’s resignation was announced, US President Barack Obama said he was thrilled by the change. “By stepping down, President Mubarak responded to the Egyptian people’s hunger for change, but this is not the end of Egypt’s transition. It’s the beginning,” he said. The demonstrators in Tahrir Square could not have put it better. Obama had become their commander-in-chief.

Obama quickly turned his fire on other Middle East governments and condemned violence against demonstrators in Bahrain, Libya and Yemen in remarks made on 18 February. That night he called King Hamad of Bahrain to urge restraint: it was as close as you could get to a rebuke for the death at the hands of Bahrain’s security forces of at least seven demonstrators.

The public response among America’s Arab allies was muted. But behind the scenes, there was alarm. Obama had broken the compact upon which US Middle East policy had been constructed for more than 55 years: as long as Middle East governments supported American strategy in the region, the US would support them.

It was almost unbelievable that a US president would hasten the fall of Mubarak, a man who had consistently bent to America’s will. A precedent, it seemed, was being set. It suggested that even if you were America’s friend and ally, the White House might turn against you.

It is more than three weeks since Obama’s call to King Hamad and conventional US policy seems to have been reasserted. Secretary of State Hillary Clinton said on 4 March that Iran was in contact with opposition groups in Bahrain and elsewhere in the region. It was the first intimation that the US believed the Islamic republic was playing a role in revolts in Arab countries. Clinton’s words were a sign that the US wanted to appease the government of Bahrain and other American allies in the Arab world.

The consequences were soon obvious. On 5 March, Saudi Arabia’s Interior Ministry said demonstrations in Saudi Arabia were illegal and unnecessary. The following day, the kingdom’s Council of Senior Ulema said that petitions calling for political reform were un-Islamic. Saudi Arabia’s pronouncements constituted the most comprehensive assertion against the right to peaceful assembly and freedom of expression voiced by any Arab government in response to this year’s events. They directly contradicted the spirit that inspired Obama’s declarations in February. The State Department on 7 March reaffirmed America’s support for the right to protest peacefully, but this was done by a press officer not Clinton. There was little conviction behind the words.

For those who believe the unrest in the Arab world is essentially the result of external manipulation, the change in America’s language this month is evidence that the Arab spring is over by US order. Conventional State Department thought is overriding Obama’s enthusiasm for radical change. Demonstrators in Saudi Arabia and other Arab countries that are US allies have been warned the White House is no longer willing to give them shelter.

It would be a mistake to conclude, however, that the challenge to the regional status quo is over. Middle East governments have been given time to devise a fresh approach that takes into account the desire for greater individual liberty that is spreading among the people of the region. The voice of freedom found by Obama has been only temporarily stilled. American Middle East policy is on the move again. Without appropriate action this summer, the autumn of 2011 could be more challenging than spring for those who rule in the Arab world.