The brutal killing of one of Lebanon’s more impressive statesmen has raised the spectre of renewed sectarian strife in Beirut, challenging the fragile stalemate that has until now prevented Syria’s civil conflict spreading west across the Ante-Lebanon mountain range.

Mohamad Chatah was one of Lebanon’s most respected politicians, a close adviser to Sunni leader Saad Hariri and a critic of local militant group Hezbollah and its Syrian and Iranian benefactors. His loss will be deeply felt in the opposition, Saudi-backed March 14th movement.

The speedy intervention of Saudi Arabia, in the form of a grant to the Lebanese army of $3bn in military equipment from France, underlines the gravity of the situation in Beirut. Both Paris and Riyadh are spooked by the targeting of a key ally such as Chatah and fear other proteges in the March 14 alliance could face a similar fate if action is not taken to restore the state’s authority.

The promised cash will be gratefully received by Lebanon’s army, which has struggled to exert its authority over the country’s territory, in particular the Syrian border, which opposition critics claim is the conduit for the terrorists’ arms. Yet it provides no guarantee that prominent Lebanese critics of the Iran-Syria-Hezbollah axis will be immune to the terrorist bullet. The silencing of moderate voices is viewed by many as a deliberate strategy to sow division in the March 14 camp, giving succour to the more militant strains of Sunni jihadism that have sought to target Hezbollah in recent months.

It remains to be seen if the Saudi-French engagement can restore stability. With political dysfunction sapping the Lebanese economy’s dynamism and violence returning to Beirut’s streets, only Syria’s President Bashar al-Assad has reason to feel contentment at the turbulent state of affairs.