By Jill Dougherty and Jamie Crawford
As news broke Monday that Syrian Prime Minister Riyad Hijab had defected, the U.S. State Department said it was "encouraged," describing Hijab as the "highest-profile official to defect from the Assad regime."
"When the prime minister of the entire government defects, that's clearly an indication that they're on the way out," acting deputy spokesman Patrick Ventrell told reporters.
But experts on Syria aren't so sure.
"The prime minister in Syria is the head of the government, but the government in Syria doesn't rule the country," Andrew Tabler of the Washington Institute for Near East Policy told CNN. "It's the regime, and the regime includes the security services, the army and the members of the Assad family."
Hijab's defection is "politically significant," Tabler believes, because it shows "political erosion" in the government.
"But it's still not a core member of the regime," he said, pointing to the fact that President Bashar al-Assad's regime is comprised of minority Alawites, while Hijab is a Sunni.
Aram Nerguizian of the Center for Strategic and International Studies agrees.
"The lack of any meaningful leadership defections from the Alawite sector of the regime is very distressing," Nerguizian told CNN's Security Clearance blog.
Sunni defections have not weakened the regime's inner core, he said, "which feels even more threatened, even more concerned, even more paranoid."
Al-Assad's inner core, Tabler said, includes about 14 people - from the president's brother and sister to the heads of various security agencies, from military chiefs and others whom the United States and the European Union have blamed for carrying out attacks on the Syrian people.
So far, says Nerguizian said, the Alawite core of the Baath party and the ruling regime are sticking with al-Assad "whether they like it or not ... stuck between a rock and a hard place."
The Alawites, Nerguizian believes, would like to find some way out that would give their community a future in terms of the economy, security and a role in politics, but the rhetoric from extremist segments of the opposition are scaring them.
"They are in survival mode. They aren't exactly at their most rational. ... They look at a defection and say, 'OK, this is a negative development, but we need to hang in there, we need to survive.'"
The result? "This a very, very messy, long-term conflict that becomes increasingly sectarian," Nerguizian said.
Even if al-Assad were to step down, as the United States and its allies are demanding, Obama administration officials agree - things could get very messy indeed.
"If Assad goes, it would depend on who left with him," Tabler said. "If it's just the Assad family and the regime's still intact, that means the regime holds hard."
It's the moderates who are defecting, Nerguizian said. "So you have a future that is increasingly dictated by the extreme on either side."
Assad's leaving is no panacea, these experts warn.
"Even tomorrow, if you have an environment where Assad and his inner circle are no longer in power, even if you had a power sharing arrangement, you are still looking at a Syria that is grappling with its own internal demons for a decade," Nerguizian said.
"It's not just about Assad. All of the politics and socio-economics over the last four to five decades, if not longer, have essentially become unhinged, and no one knows how to put them back together again. So essentially Syria is the Humpty Dumpty of the Middle East."