A year ago Barack Obama described the epic wave of revolution that had begun in Tunisia and Egypt as “a historic opportunity” for the United States “to pursue the world as it should be.” He said America must promote “change that advances self-determination and opportunity.” And he asserted that “we can make a difference” in how the uprising turns out.

Today the badly misnamed “Arab Spring” is beginning to look like an epic mess. An ugly civil war in Syria could easily spread across the Levant. In Egypt, the victory of an Islamist in a democratic presidential election has prompted a power struggle with the military. Violent political conflict continues in Yemen, Libya and Bahrain. Only Tunisia appears headed toward the new era of democracy and development that Obama promised to promote, and even there it’s not clear how tolerant a new Islamist government will prove to be.

Needless to say, Middle Easterners have been the prime makers of this muddle. But given the expectations raised by Obama, it’s fair to ask: How much of it is his fault?

I’ve been asking people in and outside the region for an answer to that over the past few weeks: Egyptians, Israelis, Russians, Saudis, Libyans. Predictably, the answers have been widely varying, and often contradictory. But there are two points of consensus: Of course the United States and its president had an influence on how things turned out; and, for the most part, it was a negative one.

Start with Egypt. Obama was foolish, say Israelis and Saudis, to abandon strongman Hosni Mubarak, a faithful U.S. ally. What the old man frequently predicted has come true: Islamists hostile to the West and Israel are about to take over the country.

Wrong, say Egyptian democrats. Obama’s fault was his failure to stand up when the Egyptian military began systematically restoring the old order — culminating with this month’s dissolution of parliament. A key turning point, they say, came in March, when the administration decided to waive congressional conditions tying U. S. military aid to democratic progress — even while the regime persisted with the trial of Egyptians working for U.S. democracy organizations.

“The message the United States sent was totally immoral,” Bahey edin Hassan of the Cairo Institute for Human Rights Studies told me last week. “It was clear all the time to the Egyptian revolutionaries that the United States cared only about those who were in power and those they thought might remain in power — the military.”

Angry after Egypt, Saudis are now fuming about Syria — where, they say, the United States is shirking its responsibility to push out the regime of Bashar al-Assad before he plunges the region into a sectarian war.

Wrong, say the Russians. By publicly demanding the downfall of the regime, Obama encouraged Assad’s opposition to take up arms. “Once again you are promoting a regime change without knowing what will come afterward,” lectured a senior Russian official visiting Washington, echoing what his boss Vladi­mir Putin said to Obama at their summit meeting last week.

Everyone (except the Saudis) points to Bahrain, an island nation in the Persian Gulf where the United States parks the Fifth Fleet. The ruling al-Khalifa family has brutally repressed demonstrations by the Shiite majority while dragging its feet on meaningful reforms. But Obama has never said this dictatorship must go; in fact, he has recently gone back to selling it weapons.

Only Libyans, liberated from Moammar Gaddafi with the help of U.S. planes, are ready to praise the president. “Without the decision of Obama to defend Benghazi, our revolution might not have succeeded,” said Mustafa Abushagur, now the deputy prime minister of a transitional government. But in the past few months the victorious rebels have been struggling to construct police forces and build a unified military. The Obama administration, they say, has been slow to help.

Taken together, these disparate comments actually add up to a coherent critique. Obama’s biggest failing in the Arab Spring is not that he chose the wrong side; it is that he has waffled back and forth. He has been consistently indecisive, irresolute and reluctant to act. As a result he has alienated both regimes and revolutionaries, and squandered U.S. leverage.

Before pushing Mubarak out, Obama embraced him; now his aides are criticizing — but so far tolerating — the military’s attempts to hang on to power. Obama insists Assad must give up power and facilitates military aid for the rebels at the same time that he endorses a U.N.-brokered settlement between the regime and opposition. He demands change in Bahrain while continuing to back the regime even when it refuses to reform.

In short, Obama has made a difference during the Arab Spring mostly by not making a difference. By failing to decisively use U.S. aid, diplomatic influence and military power to support the removal of dictators and the beginning of democratic transformation, he has helped tip the balance toward the old regimes — or chaos. No, the mess is not his fault. But he deserves a share of the blame.