US President Barack Obama will on Thursday seek to sketch a plausible policy response to the sudden, complex and often contradictory demands thrown up by an "Arab Spring" of popular revolt.
In a major speech, Obama will seek to quell domestic criticism and uncertainty in the Middle East and North Africa about the exact nature of US policy.
Obama sees "an opportunity to sort of step back and assess what we've all witnessed, the historic change we've seen," spokesman Jay Carney said.
"He'll talk specifically about ways that we can best support that positive change while focusing on our core principles: nonviolence, support for human rights and support for political and economic reform."
Carney said that the speech would make "news" and promised some "specific new ideas" about new US policy towards the region.
What Obama will not do, it appears, is use the speech to relaunch his stalled drive for Israeli-Palestinian peace -- even though Jordan's King Abdullah II on Tuesday called the struggle the "core" regional issue.
Though Obama hopes to focus on Arab uprisings, simply restating failed approaches to the Israeli-Palestinian conflict could undercut his message, causing some analysts to question the timing of the speech.
"The metric by which many in the Arab world will continue to view the United States is what we do on the Arab-Israeli conflict," said Steven Cook, of the Council on Foreign Relations.
"There really doesn't seem to me to be a tremendous opportunity here to strike out on a different course that's going to be productive."
From the first murmurings of discontent in Tunisia to the revolt that toppled Egypt's Hosni Mubarak, the crackdowns in Syria and Bahrain, and the full-scale war in Libya, Obama has struggled to frame a coherent US message.
The breathtaking speed, historical scope and complexity of change sweeping the region caught Washington, like the leaders it challenged, unawares.
"I would give the United States a B-plus in how they have handled the Arab Spring -- they have stayed out of it," said Rami Khouri, a newspaper columnist and academic at the American University of Beirut.
"But (US policy) has been hesitant, it has been erratic, it has been inconsistent."
If the US response was contradictory and complicated it only mirrored the unpredictable revolts cascading across the Arab world.
Uprisings against US-allied leaders like Mubarak and Yemen's Ali Abdullah Saleh, a key anti-terror ally, exposed a Faustian pact with leaders who oppressed their people but delivered decades of stability.
It left Obama, who ran for president as a prophet of hope, torn between ageing autocrats and youthful demands for change in a region primed with US vital interests and oil supplies.
For many Americans, the most significant foreign event of the year is the US killing of Osama bin Laden in Pakistan, a fact pointing to a key domestic audience for Thursday's speech at the State Department.
Obama may argue that bin Laden's death is a sign that Al-Qaeda's jihad is being overtaken by more positive trends encapsulated by the "Arab Spring."
Framing policy on the hoof, when unrest boiled across the Arab world, Obama said America would always support the rights of protest and free expression.
But he also sought to avoid the United States, with its tattered regional reputation, being seen as puppet master in a region scarred by colonialism and conspiracy theories.
With key US allies threatened, he also stressed that each nation was different, rejecting a doctrinal policy that might limit room for maneuver.
Obama explained his rationale in February -- after the ouster of Mubarak.
"What we didn't do was pretend that we could dictate the outcome in Egypt, because we can't," he said.
"We were very mindful that it was important for this to remain an Egyptian event, that the United States did not become the issue."
Often, however, US statements only provoked other questions, and analysts are keen to see Obama explain logical contradictions.
Many observers have asked why Washington joined a military effort in Libya, on the side of anti-Moamer Kadhafi forces, but stayed on the sidelines when ferocious crackdowns took place in Bahrain -- a key military ally.
Others wonder whether fears of regime change and chaos that would threaten Israel have caused Obama to soften the line against Syria's crackdown.
When Obama did back protestors when the tide turned against US-backed leaders -- as in Egypt and Yemen -- he ran into trouble.
Saudi Arabia was furious at Mubarak's treatment -- and along with Gulf nations appears to be stiffening its resistance to political change.
But Riyadh remains an ally Washington can ill afford to lose and is one of a number of Gulf states backed by billions of dollars of US military spending -- as a bulwark against a rising Iran.
The president must also deal with lowered expectations following his address to the Muslim world in Cairo in 2009.
"I think there is speech fatigue in the Arab world and people will not listen quite as intensely as they might have done a few years ago," said Khouri.