Sunni animosity toward the Assad regime, which is dominated by the minority Alawite sect, has deep roots. Under former President Hafez al-Assad, Syria extended its military hegemony over Lebanon and implemented an unrelenting crackdown on Lebanon's Islamists.
In Tripoli, the suppression was particularly fearsome. Islamist groups both aligned and non-aligned to the Syrian Muslim Brotherhood were routinely rounded up by security personnel and arbitrarily imprisoned, or worse.
Ahmed Qasas, a senior member of Hizb ut-Tahrir, a global Islamist organization that was banned from operating for decades in Lebanon, was one of the thousands to spend time in jail at former Syrian President Hafez al-Assad's leisure. "We were followed constantly," he told Foreign Policy at the party's Tripoli headquarters. "Most of the party's youth were put in jail. We were the most targeted by the mukhabarat [Syrian secret police]."
Hizb ut-Tahrir -- which boasts more than one million members worldwide and seeks the establishment of a global Islamic state -- has been a mainstay of public demonstrations calling for Assad's departure, flouting a ban on its gatherings with ever-increasing numbers. And politically, the party has been invigorated by the regional gains made by Islamist organizations in the wake of the Arab Spring.
"There has been more acceptance of the culture of Hizb ut-Tahrir across the region," Qasas says. "People for the first time are seriously looking for a political project and we believe that there is no project capable of change apart from ours."
Qasas is at pains to point out that Hizb ut-Tahrir does not advocate violence. At the same time, he wholeheartedly supports the Syrian rebellion against Assad: "The Syrian people have had to take up arms after the regime attacked them," he says.
Lebanon's political establishment has largely eschewed descriptions of the Syrian conflict as a struggle between Sunnis and Shiites. Those sympathetic to the revolt depict it as a people's struggle for freedom, while those opposed paint it as a sovereign administration fighting off foreign terrorist intervention. However, in the absence of a cohesive political opposition to Assad, less orthodox figures like Assir have filled the political vacuum by presenting events as an epoch-defining showdown between rival Muslim sects.
Assir, for his part, blames the international community's inaction for the presence of al Qaeda-inspired groups in Lebanon, and maintains that he would support any group -- no matter how extremist -- that struggles against the government in Damascus.
"In battle -- in history -- there is no clean kill," the firebrand cleric says. "You always have inappropriate things that happen that people don't agree with. I want to see Bashar killed in battle."