This summer marked the tenth anniversary of the Second Lebanon War between Hezbollah and Israel, and a tenuous peace continues to hold even as tensions run high. Over the past decade, the two sides have exchanged only limited strikes, though aggression has increased since Hezbollah’s involvement in the Syrian civil war. However, while conditions along the Lebanese-Israeli border appear unchanged, much has transpired since the war that will deeply impact future struggles. And though it may be comforting to assume that a militarily superior Israel would handily defeat Hezbollah in the event of a war,  and that this knowledge will deter Hezbollah from attacking Israel, the reality may be quite different. Indeed, a future war would be bloody and difficult for Israel to win without sustaining heavy casualties. As such, Hezbollah’s current restraint may be a product of a different source.

Over the past decade, Hezbollah’s military capabilities have greatly advanced. With an annual income of almost US$1 billion, millions in annual funding from Iran, and connections to Syria and Russia, Hezbollah has been able to increase its arsenal from approximately 15,000 rockets to almost 100,000, including missiles with ranges of over 300 kilometers, a distance that covers almost all of Israel. In addition, Hezbollah has appropriated Yakhont anti-ship cruise missiles, which would enable the group to be more active in the maritime theater. This growth in armaments has been complemented by the invaluable experience its members have garnered in Syria. While Hezbollah has lost at least 1,000 fighters defending Assad, those who have returned to Lebanon boast experience in formal combat using sophisticated equipment. Consequently, though Israel has killed some of Hezbollah’s leaders, the rest have had the opportunity to direct large-scale offensive operations. Rather than weakening the organization, then, Hezbollah’s involvement in Syria may have primed the organization to once again consider provoking a conflict with Israel.

Moreover, Hezbollah’s entrenchment in Syria opens the door to a second front from which to attack Israel, in addition to its traditional base of operations in Lebanon; most of the recent skirmishes between Israel and Hezbollah have occurred along this new Syrian front. Predicting that Hezbollah will take advantage of this space in the future, the Israel Defense Forces (IDF) introduced a new military exercise to prepare for a battle on both fronts. Additionally, Israeli Prime Minister Benjamin Netanyahu has sought assurances from Russian President Vladimir Putin that Moscow’s forces in Syria would coordinate with Israel to prevent a Hezbollah-Syria-Lebanon axis. While Putin has been receptive thus far, such a commitment may not hold fast in a situation of actual war.

These changes have been accompanied by a marked shift in the Israeli perspective on the militant organization. While in 2010, now-IDF Chief of Staff Lieutenant General Gadi Eizenkot dismissed the danger of Hezbollah as overblown, he recently reversed course, declaring Hezbollah, with its vastly expanded arsenal and training and support from Iran, the IDF’s “main rival” and the “most severe threat” that Israel faces. A war now, as Israeli Major General Herzl “Herzi” Halevi has stated, would cause far more Israeli casualties than in the 2006 war. Israeli fears have been further heightened by reports that Hezbollah is creating new attack tunnels, transporting rockets to the border, and monitoring IDF activity, which the IDF believes mirrors Hezbollah’s behavior immediately before the outbreak of the 2006 war.

While Israel still maintains a qualitative military edge, there is a high probability that in the next few years Hezbollah will acquire terminal guidance technology, enabling it to launch precision-guided missiles that can deliver half a ton of high explosives within meters of targets. This would be particularly damaging to Israel, considering Hezbollah’s tendency to target civilian infrastructure. For example, Sayyed Hassan Nasrallah, Hezbollah's secretary general, recently threatened the destruction of the ammonia chemical plant in Haifa, which would cause tens of thousands of deaths.

That Hezbollah has developed the ability to inflict significant damage suggests that the prevailing narrative of a more powerful Israel successfully deterring Hezbollah may not be a fully accurate assessment. Rather, there are likely other key factors that are currently holding Hezbollah at bay. While combatting Israel serves as Hezbollah’s raison d’etre, ensuring Assad’s survival is currently a more pressing concern. Hezbollah has historically used Syria as a conduit for weaponry and a source of staunch support, and the collapse of its ally would mean losing Syria’s backing and result in isolation from the rest of the Arab world, especially Iran. Perhaps even more importantly, Iran, Hezbollah’s principal financial supporter and an authoritative voice for Nasrallah, has prioritized defending Assad.

Iran may not be the only international actor giving Hezbollah pause. This past year has witnessed a dramatic decline in Hezbollah’s relationships with the Sunni Arab states. Last January saw the Saudi execution of prominent Shia cleric Nimr al-Nimr, a move which Nasrallah harshly denounced. In March, Saudi Arabia led the Gulf Cooperation Council in collectively designating Hezbollah as a terrorist organization. This was followed by a parallel Arab League declaration and has been accompanied by Hezbollah’s growing unpopularity among the Arab Gulf public. Perhaps in response, in September, Nasrallah declared Wahhabism, Saudi Arabia's dominant Islamist faith, to be "more evil than Israel."

Still, countries outside of the immediate Saudi umbrella do not seem to be as committed to the Saudi-led position. Both Lebanon and Iraq dissented in the Arab League vote, and Egypt, which in February hosted Hezbollah to discuss coordination in the Levant, has avoided referring to the organization as a terrorist entity. Moreover, the Gulf states primarily denounce the organization insofar as it is an Iranian proxy fighting against their coalition in Syria; if a political settlement in that arena were eventually reached, it is possible that the Arab states would perceive Hezbollah more as a representative of the Palestinian cause and consequently extend renewed support.

In such an eventuality, the sway that the Arab states hold on the international stage could weigh heavily against Israel, constraining its options. This capability was most recently displayed during the 2014 Gaza War, in which the Arab League pushed for a UN Security Council meeting and expressed its support for numerous Jordanian-led resolutions demanding an end to the violence and condemning Israeli aggression, pressuring the United States and Israel to bring the war quickly to a close.

This places Israel in a challenging position. While Jerusalem regards the instability and extremism emanating from Syria with concern, it has until now benefited from the sectarian rift that has developed as a result of the struggle between Iran and Saudi Arabia and the consequent weakening of Hezbollah’s regional position. However, under the surface, the military threat has likely grown, while the geopolitical alignment that limits Hezbollah’s aggression may not last indefinitely. This suggests that Israel needs to be looking beyond military preparations and taking advantage of the current climate to more comprehensively develop its deterrence against Hezbollah.