Now, almost two months after Obama's statement, U.S. officials have concluded that their hopes for Assad — never high in the first place — were misplaced. The Syrian dictator hasn't led, and he hasn't gotten out of the way. Instead, he has tried to wear down the opposition with a combination of fierce repression and sporadic tolerance. (It's a strategy that has worked for the autocratic regime in Iran, which sent advisors to Damascus to help Assad stay in power.)
It is a matter of growing frustration to human rights activists that the Obama administration still hasn't bluntly called on Assad to step down. Instead, U.S. officials have continued to issue warnings. "The Syrian government is running out of time," Secretary of State Hillary Rodham Clinton said earlier this month. "They must begin a genuine transition to democracy." But the U.S. still stops short of declaring Syria's dictator illegitimate.
Why? The answer is a lesson in the limits of American power and the dilemmas of promoting regime change in a volatile part of the world.
U.S. officials have concluded that Assad's regime is unlikely to survive, but they're not sure how long it will take for him to fall. Publicly demanding his ouster could raise unfounded expectations of direct U.S. intervention, a step the administration is far from ready to take. And if Obama were to call on Assad to quit with no result, that would leave the United States looking weak, a lesson that Western powers have learned again in Libya this summer.
The United States and its allies have imposed economic sanctions on Syria, and the administration is asking Russia and European countries to do more. But those measures are unlikely to have an immediate or decisive impact. Determined dictators rarely fall from power merely because of economic misery. (Think of North Korea and Zimbabwe.)
Instead, unsurprisingly, the most important actors in the Syrian drama are Syrians. Can the government remain cohesive despite what looks like uncertainty and vacillation at the top? And will the opposition remain committed and even grow, especially in the Sunni Muslim centers of Damascus and Aleppo, where the government still has many supporters?
Ordinary Syrians have braved bullets and truncheons to demonstrate against the regime. But so far the opposition is still disorganized, a constellation of mostly local committees that reflect Syria's fragmentation among ethnic groups and religious sects. "They have improved vastly, but they are still organizing themselves," said a U.S. official who has been talking with opposition figures.
The opposition has been careful not to name individual leaders, in part out of fear that the regime would quickly eliminate them. If Assad fell tomorrow, it's not clear who would succeed him, or how.
So the focus of American policy has turned to practical ways to help the opposition succeed. That has included efforts to provide Syrians with more access to the Internet free from government surveillance. It has also included increasing pressure on the Syrian government to allow opposition meetings and demonstrations.
"What we're trying to do is push the Syrian government toward allowing space for dialogue, credible dialogue; to allow the opposition to have coordination meetings; to create forums where people can talk," the official said.
On Friday, for example, the U.S. ambassador in Damascus, Robert S. Ford, did something daring for a diplomat: He drove to the opposition-dominated city of Hama and met with demonstrators before their weekly protest. The move was intended in part to deter the regime from shooting at the demonstrators, and, in fact, no shootings were reported.
More controversially, perhaps, the administration is still hoping that Sunday's government-opposition dialogue sponsored by the Assad regime could turn into something useful. "A dialogue has to be attempted. It has to be tried," the official said.
The United States essentially is trying to help arrange a slow unraveling of the Syrian regime rather than an abrupt collapse. In that sense, Syria is very different from Tunisia or Egypt, where the Obama administration endorsed revolutions that were already well under way, or Libya, where it has backed an armed uprising that started without U.S. help.
Even some activists in Syria's opposition agree that a public U.S. demand for Assad to step down is not the top item on their wish lists.
"This is a secondary thing," said Radwan Ziadeh, a Washington-based opposition member. "A clearer statement from Obama would be good … but the most important thing for us is more international pressure, more sanctions with teeth."
Such a statement is likely to come eventually if Assad gets closer to falling — and the opposition looks more prepared to take over.
"It's something we actively debate," the U.S. official said. "But it has to be with the lead of the Syrian people."
This isn't exactly leading from behind; it's more like helping from offstage. But one of the lessons of Tunis, Cairo and Tripoli has been that White House statements aren't as important as they look. It's what happens on the ground that counts.