Editor's note: Marc Lynch is director of the Institute for Middle East Studies at George Washington University, editor of the Middle East blog on ForeignPolicy.com, and author of "The Arab Uprising: The Unfinished Revolutions of the New Middle East" (PublicAffairs).
(CNN) -- The stunning assassinations of several key Syrian leaders and the outbreak of serious combat in Damascus last week momentarily held out the possibility that President Bashar al-Assad's regime will rapidly fall. Many hoped for a cascade of defections, a rise in popular demonstrations and a rebel surge to bring down the government.
Those hopes were exaggerated, fueled by a feverish rumor mill, psychological warfare and notoriously unreliable information coming out of Syria. While the regime has been shaken, its military capability stands as demonstrated by its bloody reassertion of control over Damascus. Along with the support of Russia, its determination to survive at any price could draw out the endgame.
The assassinations struck at the heart of the security machine that sustains the regime, and they highlight the extent to which political and military tide has long since turned against al-Assad. The assassinations were more of an inflection than a turning point.
Diplomatically isolated, financially strapped and increasingly constrained by a wide range of international sanctions, al-Assad's regime has been left with little room to maneuver. It resorts to indiscriminate military force and uses shabiha gangs and propaganda to inflict terror.
The government's violence against peaceful protestors and innocent civilians has been manifestly self-defeating. Al-Assad has failed to kill his way to victory. Day by day, through accumulating mistakes, the regime is losing legitimacy and control of Syria and its people.
Nonetheless, it's premature to think the end is close.
The opposition's progress, reportedly with increasing external funding and training, has put greater pressure on al-Assad's forces. But the opposition's military success has exacerbated the fears of retribution attacks and a reign of chaos should the regime crumble.
The much-maligned political efforts of U.N. special envoy Kofi Annan, backed by the United States, were meant to find a political solution that could prevent precisely such a deterioration of the situation on the ground.
Now, even if al-Assad's regime collapses, violence may prove difficult to contain given that the country is deeply polarized and awash in weapons. Al-Assad's end could pave the way for an even more intense civil war.
Making matters worse, the continuing fragmentation among the Syrian opposition groups raises deep fears about their ability to unite themselves or to establish authority. Few foundations exist for an inclusive and stable political order after al-Assad.
The Obama administration was prudent and wise to avoid a direct military intervention in Syria. A legion of pundits deemed an American military role necessary for any progress against al-Assad. Clearly, it was not.
Indeed, a limited intervention would likely have strengthened al-Assad's hand at home and abroad. Had the U.S. chosen to carry out airstrikes to enforce a no-fly zone or safe havens, Syria's crisis would likely be no closer to resolution but America would be deeply embroiled.
Some have suggested that the U.S. should provide weapons to favored factions among the opposition groups. This, too, is a dangerous idea. There is no reason to believe that these factions would reward the U.S. with loyalty.
What the U.S. should do is focus its efforts on maintaining international pressure and sanctions on al-Assad while preparing for a transition. It should disseminate credible information about the regime's atrocities. It should aggressively plan to bring the architects of Syria's well-documented massacres to face international justice. (It is far too late for an amnesty for al-Assad and his top aides, but lower-level officials should be offered a deadline to defect to avoid prosecution.)
When al-Assad falls, the Syrian opposition will urgently need to unite Syria and short-circuit the emergence of an insurgency from supporters of the old regime. Preventing reprisal killings, including all groups in the political process, and incorporating public servants who are not implicated in war crimes will be essential.
The U.S. should help prepare the Syrian opposition for the challenges of governing a fractured country by facilitating the negotiation for a representative and unified political entity, with a greater role for pragmatic leaders on the inside. It could send a small U.N. stabilization force to Syria to as a monitor. And it will have to persuade the armed insurgency to police its own ranks to avoid sectarian fights.
The hopes of a soft landing in Syria have been destroyed by the regime's violence. The U.S. must now try to deal as best it can with the grinding struggle to come.
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The opinions expressed in this commentary are solely those of Marc Lynch.