The Syrian Civil War continues to frustrate the international community. A solution to effectively stop the slaughter or stem the flow of refugees has yet to be found.  What seemingly began as an effort to free the Syrian people from a tyrannical dictator has been transformed into a proxy war, with multiple opposition forces and their backers fighting a Syrian army bolstered by Iranian-backed Hezbollah fighters.

For years, Syrian strongman Bashar Al-Assad has permitted and facilitated the flow of Iranian agents, money, and weaponry to Hezbollah in Lebanon. Hezbollah’s growth has enabled Iran to transport its hardline-Shiite ideology to the Levant while also expanding Iranian reach and capability to Israeli, as well as Western targets and interests.

Hezbollah’s effort in Syria on behalf of the Assad regime is well documented. For example, in early 2013, Western intelligence accused Hezbollah and Iran of cultivating terrorist networks in order to maintain influence in Syria if Assad fell. Hezbollah later admitted it was fighting on Assad’s behalf in Syria.

The costs to Hezbollah resulting from its involvement in Syria have been high. For example, in May 2013, Israel bombed Hezbollah weapons sites in Syria to prevent the transfer of Iranian-made missiles into Lebanon. Hezbollah was also involved in a costly battle in late May to wrest the Syrian town of Qusair from rebel hands. More than 500 rebels were reportedly killed during the almost month-long battle, as was Hezbollah Secretary General Hassan Nasrallah’s brother, Khader.

In all, Hezbollah has reportedly lost 1,000 fighters in Syria, and in recent months, the group appears to have taken a page out of Israel’s playbook by building a security zone along the Syrian/Lebanese border manned by 1,000 fighters, to keep Sunni terrorists out of Lebanon.

Some interpret this security zone as a sign of Hezbollah weakness – the decision to pull back, rather than pushing forward. The terror group has taken heavy losses and may be overstretched. More Hezbollah fighters are mobilized now than even during the 2006 war with Israel, when Hezbollah relied heavily on Iran-supplied rockets to be able to strike from a distance.

The future of Syria is clearly in the vital interest of Iran. And the high costs being borne by Hezbollah prove it.