Assad must go. Three short words — one protracted policy debate.

Back in the summer of 2011, those words, or their equivalent, became known among makers of U.S. Middle East policy as “the magic words” — words that President Obama, cautious about the consequences, had not yet decided to utter about Syrian dictator Bashar al-Assad.

For five months there was mounting domestic political pressure on Obama to do so, as the Arab Spring protests demanding greater freedom and an end to corruption spread, triggering a harsh crackdown.

Finally, on Aug. 18, then-Secretary of State Hillary Rodham Clinton said, “The transition to democracy in Syria has begun and it’s time for Assad to get out of the way.” Obama simply issued a statement: “For the sake of the Syrian people,” he said, “the time has come for President Assad to step aside.”

The route Obama took to that declaration says a lot about where he is today. The president’s insistence that Assad must go has been his only true red line in the Syrian conflict. The red line he drew, and then withdrew, about repercussions of Syria’s use of chemical weapons didn’t happen for more than a year. But Obama’s determination to topple Assad remains one of the main points of friction between the United States and Russia in Syria.

The alliance between Russia and the regime of Bashar al-Assad goes back decades. Here's a bit of historical context that explains why Russia is fighting to prop up its closest ally in the Middle East. (Ishaan Tharoor and Jason Aldag/The Washington Post)

It might also be boxing in the United States as it struggles to focus attention on the Islamic State in Syria. In the past four years, the Syrian opposition’s focus on the battle to oust Assad, and Assad’s own brutal response, has created a vacuum partially filled by the Islamic State. Now as Russia comes to the defense of Assad, its initial hits targeted U.S.-backed opposition forces, not the Islamic State.

In addition, Obama’s vow to oust Assad has created tension with Russia’s President Vladi­mir Putin, who supports Assad. That has been one obstacle to restarting failed U.N. and Arab League-sponsored talks on ending the Syrian conflict. Now Obama has said that Assad need not leave during negotiations to end Syria’s civil war, but he still insists that Assad must ultimately step down and make way for a new regime.

The debate inside the Obama administration in 2011 also sheds light on how the president thinks about the U.S. role in overthrowing a foreign dictator — especially one who had been courted on matters of common interest. Obama has flipped back and forth on this issue: In 2002, he opposed the invasion that overthrew Saddam Hussein, but later supported the bombing that helped bring down Libyan leader Moammar Gaddafi. This year at the United Nations he noted that the international strategy in Libya had been flawed, saying, “Even as we helped the Libyan people bring an end to the reign of a tyrant, our coalition could have and should have done more to fill a vacuum left behind.”

Today many of the people who criticized Obama in 2011 for being slow to call for Assad’s overthrow fault the president for not taking military action to back up his call. Others say if he had not been prepared to back up the call, he shouldn’t have made it all.

Bruce Jones, vice president of the foreign policy program at the Brookings Institution, said the call for Assad’s exit “was a classic case of talking loudly and carrying a small stick.” He calls it “a fundamental mistake of policy. If you call for Assad to go, you dramatically drive up the obstacles to a political settlement. If you’re not insisting on him leaving there are more options. If you say Assad must go as the outcome of a settlement he has the existential need to stop that settlement.”

‘The Syrian track’

For the two years before the Arab Spring spread to Syria, the United States had been reaching out to Assad to promote “the Syrian track” in peace talks with Israel. The administration allowed the shipment of some dual-use technology, most significantly lifting restrictions on U.S.-manufactured spare parts for the Syrian airline. And in early 2011 there was a sense that Syria could be the key to a Mideast peace deal.

In January 2011, just two months before protests broke out in Syria, the United States posted an ambassador to Damascus for the first time in six years; diplomatic representation had been withdrawn in 2005 after Syria was accused of complicity in the assassination of former Lebanese prime minister Rafiq al-Hariri.

The month before the protests began, Frederic C. Hof, then a State Department official trying to forge a peace accord between Syria and Israel met with Assad in Damascus. Arab Spring movements had already broken out in Tunisia, Egypt and Libya, but Assad was business-like and did not mention or comment on them, said Hof, now a senior fellow at the Rafik Hariri Center for the Middle East.

It was Hof’s fourth meeting with Assad. It would turn out to be the last.

After protests broke out in the southern Syria city of Daraa, the administration urged Assad to adopt genuine reforms and stop violence against peaceful demonstrators.

In a March 28 television interview on CBS, Clinton said, “We deplore the violence in Syria,” but she expressed hope that the Western-educated Assad would change his approach. She said, “There is a different leader in Syria now. Many of the members of Congress of both parties who have gone to Syria in recent months have said they believe he’s a reformer.”

But domestic critics faulted the administration for repeating what it did in Egypt in February: standing by longtime leader Hosni Mubarak as his support collapsed until 10 days before he stepped down.

“For several months, though pressures were building, the president and administration resisted saying that” Assad must go, recalled Dennis Ross, who was then a special assistant to Obama and a National Security Council senior director. Instead, Ross said, the administration would issue “statements like ‘He’s losing his legitimacy.’ ”

Ross recalls that “one of the reasons Obama did resist [calling for Assad’s exit] was that he understood that if he said it there would be an expectation and another gulf between what you say and the reality.”

Obama also had his hands full. The Syria drama was playing out at the same time as fighting in Libya; in March U.S., Canada and European allies flew sorties and imposed a no-fly zone. Obama, already trying to wind down two wars, was not willing to get the U.S. ground troops bogged down in yet another country’s internal strife.

Obama had thought about the U.S. role on intervening to oust dictators ever since 2002, when as an Illinois state senator he opposed the imminent U.S. invasion of Iraq. Obama called Hussein a “ruthless man” and “a brutal man” but said that Hussein posed “no imminent and direct threat to the United States or to his neighbors.” Instead of invading Iraq, he said, the United States should hold back because Hussein could “be contained until, in the way of all petty dictators, he falls away into the dustbin of history.”

Nonetheless, he joined the Libya air campaign because it was originally designed to prevent a humanitarian disaster; administration officials feared Gaddafi would massacre civilians in Benghazi. But the mission soon grew into providing air cover for foes seeking to bring down the Libyan leader.

In the absence of direct U.S. intervention in Syria, some administration members hoped that imposing economic sanctions would undercut Assad’s support among the merchant class and ramp up pressures for reform from within. There were also signs of dissent within the regime. On April 29 and May 18, Obama issued executive orders sanctioning and freezing assets belonging to Assad and half a dozen top Syrian officials. But Assad stood firm.

Many White House advisers wanted the president to call for Assad’s ouster, so in July, they organized an interagency group to consider the “magic words.”

“The White House had the strongly held belief that Obama needed to be on the right side of history,” Hof said. “The prevailing belief was that Assad would not last too long. If the Arab Spring had swept away Mubarak and others, and all these people were giants, who was Assad to resist this tidal force?”

At the State Department, however, there were doubts. Officials said that if Obama were to call for Assad to step aside, the administration would need a strategy to make it happen. Hof said, “Even though Assad was not as impressive as the other four who were swept aside, he still had a lot of resources and the ability to turn this into a largely sectarian conflict since his military forces were predominantly of the same sect as he was.”

If Obama was going to say the magic words, he was determined not to be alone. The administration coordinated with European allies and on the same day as Obama’s statement, the leaders of France, Germany, Britain and the European Union also called on the Syrian leader to step aside.

Obama also telephoned Turkish leader Recep Tayyip Erdogan about two weeks before issuing his statement, giving Erdogan advance notice.

And Obama also unveiled new economic sanctions that froze Syrian government assets within the United States and prohibited U.S. firms from buying, selling or processing Syrian oil.

Seeking a new approach

Two days after the statement was issued, rebels launched an attack on Tripoli. Gaddafi fled before being captured and killed later that month.

Four years later, however, Assad is still standing. Should Obama have been more restrained to avoid boxing himself into an untenable position?

A former senior administration official, who was at the center of the debate over calling for Assad’s removal, said that “initial decisions to not engage more were made against the backdrop of most analysts’ belief that Assad would be gone in four to six months.”

However, he said, “after awhile it was apparent that no matter what you did militarily you wouldn’t be able to affect whether he was gone or not. We had been through instances in last 15 years where we didn’t have a clear concept of where we were going and it was not in the interest of the United States.”

Others see it somewhat differently. “I’m a big believer that good statecraft always involves marrying your objectives and means,” Ross said. “If you don’t feel you have the means, it probably makes more sense to be careful about how you frame your objective.”

But if the United States is not going to intervene militarily, how can it help domestic forces seeking greater democracy?

“In some ways, those of us who want to see more action will often take whatever we can get. So if we’re not willing to do more, at least we can make a statement to let people know you’re with them,” said Anne-Marie Slaughter, who earlier had been Clinton’s director of policy and planning at State and who in 2011 was pressing for a clarion call on Assad from the administration. “Now many of us think if that’s all you can do, maybe you’re better off not speaking. If we’re going to get people’s hopes up when we’re not willing to do more, we need to be honest about that and maybe it’s better to remain silent.”

Some foreign policy experts say in the end, it didn’t matter because Assad was set on a course of violent suppression of protests that would make him unacceptable to most Syrians regardless of what Obama said.

“This is a guy whose portfolio of war crimes and crimes against humanity is very impressive,” Hof said. “If you’re looking for someone able to inspire confidence, this is the last guy you would look for to provide that.”

Meanwhile, Obama is searching for a way to bring a new coalition together and focus fighting on the Islamic State.

“Yes, realism dictates that compromise will be required to end the fighting and ultimately stamp out ISIL,” Obama said at the United Nations on Sept. 28, using a common acronym for the Islamic State. “But realism also requires a managed transition away from Assad and to a new leader and an inclusive government that recognizes there must be an end to this chaos so that the Syrian people can begin to rebuild.”

“There is a fundamental tension between those words,” said Derek Chollet, who had jobs at the State Department, National Security Council and Pentagon under Obama. “For those who say this needs to be managed, it may be hard to get a transition.”

Greg Jaffe contributed to this report.