The camp of outgoing prime minister Saad Hariri, son of the slain five-time premier, has since "suffered a number of setbacks," said Asaad AbuKhalil, professor at California State University and author of a political blog.
"But it would be too soon to declare its death because the factors that gave rise to the movement remain," AbuKhalil told AFP.
Monday marks the anniversary of the February 14, 2005 bombing that killed Sunni billionaire Rafiq Hariri and 22 others, setting in motion a wave of demonstrations demanding the withdrawal of Syrian troops.
Many Lebanese see the events as having set the precedent for the fall of Egypt's president Hosni Mubarak and for last month's revolution in Tunisia.
The protests forced Damascus to withdraw its troops under massive international pressure after 29 years of military domination over Lebanon, igniting a sense of euphoria among millions that was to prove short-lived.
For the past two years, a bitter political battle has revolved around the Special Tribunal for Lebanon (STL), a controversial UN-backed court expected to implicate members of the Iranian-backed Hezbollah in the Hariri murder.
Son and political heir Saad Hariri heads the anti-Syrian "March 14" coalition, which rallied massive popular support after his father's death and went on to win two legislative elections.
But today the tables have turned for Hariri and his Western-backed allies.
"Six years on, things are looking pretty grim for the original coalition formed after Hariri's assassination," said political commentator Nicholas Noe, editor of a book on Hezbollah.
"The deepest cut over the years has been the issue of the tribunal," Noe added. "Those forces opposed to the tribunal have been able with a fair degree of success to undermine its credibility."
March 14's popularity has waned as Damascus regains sway over its smaller neighbour and Saad Hariri -- whose unity government was toppled last month in a feud over the tribunal -- finds himself in the opposition.
Hezbollah and its allies on January 12 withdrew their ministers from a unity government, forcing its collapse, and tapped Sunni billionaire Najib Mikati to head the next government.
Even before its formation, Mikati's cabinet has earned the moniker "Hezbollah's government" from the Hariri camp, who say they will not join.
Prior to the cabinet breakdown, the Shiite militant movement Hezbollah waged a relentless and, experts say, relatively successful public campaign to discredit the STL and the Hariri government that backed it.
"The battle has long been about the Lebanese public's perception of the tribunal's credibility and legitimacy," said Elias Muhanna, author of another political blog and a PhD candidate at Harvard University.
"And I think that (the Hezbollah camp) has been more adept at shaping that perception."
The Syrian- and Iranian-backed group, which dismisses the STL as a US-Israeli conspiracy, months ago revealed what it says was evidence that its archfoe Israel had toyed with telecom evidence used in the case.
A local pro-Hezbollah television channel has also aired a series of leaked recordings of the outgoing premier's interviews with UN investigators dating back to 2007 in which he called Syria's President Bashar al-Assad an "idiot."
Although Hariri had initially pointed the finger at Assad for his father's murder, he later cosied up to his northern neighbour, visiting Damascus on several occasions since his 2009 appointment as prime minister.
"I would not underestimate the impact of the ... leaks in that they showed the extent to which the actual legal proceeding of the position of the Hariri court had been tainted by utter unprofessionalism," said AbuKhalil.
"The way Hariri spoke, so vulgarly, made him ... unseemly to some," he added. "Here was Hariri rallying his community against Syria, only to have his followers witness how he crawled right back to Syria."