Salim Idriss, the former Syrian army general who now heads the rebel Free Syrian Army's military command, is a key interlocutor for the West and could be the conduit for future US military aid.
In the West, Idriss is seen as a moderate voice, a counterbalance to some of the more unsavoury radicals fighting within the opposition's ranks.
When US Republican Senator John McCain slipped into Syria briefly last month, he met with Idriss, and has since praised the 55-year-old as a figure the United States can work with.
"General Idriss and his fighters share many of our interests and values," McCain said in a statement earlier this month.
"They are fighting our common enemies every day in Syria. They are our best hope for a moderate Syria free from (Syrian President Bashar al-)Assad, Iran, and Al-Qaeda."
A former military engineer, Idriss defected in July 2012, and was elected chief-of-staff for the newly formed military council overseeing the Free Syrian Army in December of that year.
Stocky and mustachioed, Idriss hails from the central province of Homs and has at times shown a penchant for fiery rhetoric.
Last month he warned the Lebanese Shiite group Hezbollah that rebels would "hunt" its members "even in hell" if they continued to fight alongside the Syrian regime.
Idriss studied engineering in Damascus and received his PhD in Germany. He speaks English, Arabic and German and is married with three daughters and two sons.
Syrian activists and opposition members have largely positive things to say about him, but there are questions about the extent to which he commands fighters on the ground.
"Idriss is seen more as a political leader than as a field commander," Elizabeth O'Bagy of the Institute for the Study of War wrote in March this year.
"He was not chosen because of his command of significant ground forces or his operational effectiveness, but instead for his ability to serve as a political representative... and for his personal relationships to foreign officials, and more importantly, to suppliers," she wrote.
"Because Idriss' role is perceived to be more political than military, rebel commanders do not see him as the head of a top-down chain of command."
For whatever access he lacks on the ground, Idriss has taken advantage of his international presence to call loudly and frequently for military aid.
And he has not hesitated to wield the spectre of a power vacuum ripe for exploitation by forces like the Al-Qaeda-allied Nusra Front rebel group if military aid is not forthcoming.
"The United States' hands-off approach in Syria is only exacerbating the conflict by allowing anti-American and extremist elements to gain a stronger foothold in the country," he wrote in a March opinion piece in Foreign Policy Magazine.
With Washington's decision to provide "military support" to the rebels, Idriss is expected to become a key conduit.
That could give him greater leverage when it comes to wrangling the diverse forces fighting on the ground under the rebel banner, according to Charles Lister, an Analyst at IHS Jane's Terrorism and Insurgency Centre.
"Should the US decide to send weapons into Syria via Idriss, it will certainly raise his profile and influence within the wider insurgency," Lister told AFP.
"The prospect of holding the key to solid supplies of weaponry will make Idriss the centre of many rebel groups' attentions."
But he warned that the "rising profile" of Islamist groups among the rebels, each with their own supporters, "means we may now find ourselves in a battle for influence between moderate and more Islamist rebel groups and their respective backers."