About three months ago, Hezbollah Secretary-General Hassan Nasrallah decided to send his elite military units to Syria to support the military efforts of the regime of President Bashar al-Assad in facing opposition forces. Deputy Russian Foreign Minister Mikhail Bogdanov reported that Nasrallah had told him, when he met with him on April 27 during a visit to Lebanon, "I intervened in Syria to save the regime, which was on the verge of collapse."

Hezbollah's participation in the battle of Qusair — which, according to sources here in Beirut, included approximately 3,000 fighters — led to a change in the balance of the military conflict in Syria in favor of the regime. 

According to a Hezbollah source speaking with Al-Monitor on condition of anonymity, it was assumed that, according to the plan, the regime would continue its cooperation with Hezbollah to gain control of the outskirts of Damascus, via a battle in eastern and western Ghouta, as well as through beginning another battle in the Qalamoun region. The latter is adjacent to the Lebanese border facing the western Bekaa valley, and is characterized by rugged terrain. It was also assumed that these two battles would be followed by a battle for Aleppo, which is seen as a battle that would, to a large extent, decide the overall internal Syrian conflict. However, this plan, by which the Syrian army — along with strong operational military support from Hezbollah — would take the reins of the military battle, stopped the day after the US declared that it was prepared for a military strike against the regime against the backdrop of Western accusations that it had used chemical weapons in the Damascus countryside. 

Within Hezbollah, this development is seen as a very dangerous turning point affecting all paths of the Syrian crisis from its outbreak until now. The same source said that the international dimension of the Syrian crisis has entered a new phase. Its role is transforming into direct intervention in the events, whereas it previously involved indirect action through providing arms and intelligence to the Syrian opposition. But that same source said that the expected Western military strike will bring the whole region into the conflict and will result in the collapse of red lines. For US President Barack Obama isn't the only one in the region who has red lines. The Supreme Leader of the Islamic Revolution Ayatollah Ali Khamenei also has red lines, most importantly preventing the fall of the regime in Syria and protecting the Islamic resistance in Lebanon.