Source National Interest

WASHINGTON, US: The Israeli strike on Hamas’s political leadership on Tuesday threw wide open a new stage of escalation in the ongoing Israel-Gaza conflict. 
Among the dead was Saleh al-Arouri, an agile strategist, one of the founders of the Qassem Brigades, and a significant liaison to Iran’s wider network of fighters committed to fighting Israel. 
The scope and timing of the response to the targeted assassination by regional proxies, chief among them Hezbollah, will influence the evolving redlines of the belligerents in the coming days and weeks.
Over a few fateful days, the balance of deterrence between Israel and Iran-backed armed proxies has tipped to the brink. 
On January 1, Iran dispatched IRIS Alborz to the Red Sea, threatening the U.S.-led maritime coalition deployed to stop Yemen-based Houthi attacks on one of the world’s most critical shipping lanes. 
A day later, a targeted drone strike killed al-Arouri in a Hezbollah stronghold in Beirut, violating Lebanon’s state sovereignty and dealing a blow to both Hezbollah and Hamas. 
On January 3, over 103 were killed—hundreds more injured—at a memorial ceremony in Iran marking the fourth anniversary of the U.S. killing of Revolutionary Guards general Qassem Suleimani in Iran. 
While the Islamic State terror group has claimed responsibility for the attack, the high death toll has shocked the country and will only raise the stakes in a region on edge. 
Iran has refrained from entering a direct confrontation with the United States and Israel to date. 
While top Iranian officials have vowed revenge for the twin bombings in the city of Kerman, “strategic patience” rather than saber-rattling is more probable in the short term. 
Despite the flare-up, major players embroiled in this war—Israel, the United States, and Iran—are in no haste to greenlight a major escalation that would drag them and their allies into a war with no end. 
However, the pace and pitch of recent provocations may mean that any misfire or miscalculation could bring forth unintended consequences.
As Hezbollah likely plots its response to Saleh al-Arouri’s killing, it undoubtedly has disruptive, lethal means of violence in its arsenal. 
But its options are not limitless. In 2010, U.S. Defense Secretary Robert Gates commented that Hezbollah possesses “...far more rockets and missiles than most governments in the world.” 
The stockpile has expanded significantly in the intervening years, mainly sourced from Iran via Syria. 
Yet a retaliation against Israel that crosses a new redline may not serve Hezbollah’s ultimate interests.
The international and regional knock-on effect for Lebanon, a quasi-failed state with a heavily beleaguered economy, would likely be debilitating. 
Hezbollah is not as popular as it was in 2006 when Lebanon went to war with Israel, according to Kamal Alam, a nonresident senior fellow at the Atlantic Council, and with Lebanon now dubbed the “Somalia of the Mediterranean,” Hezbollah may hesitate before recklessly gambling away its remaining leverage over the non-Shia community there.
But Hezbollah will feel pressured to respond in a way that appears commensurate in the eyes of its own supporters. 
While what this may look like cannot be easily predicted, there are a few likely possibilities. 
Hezbollah may show restraint, giving Hamas leeway to design its own response. 
Hezbollah has been engaged in regular cross-border shelling from southern Lebanon against Israel since the war began. 
Hezbollah’s use of newer weapons with higher precision capability or missiles fired deeper into Israel, targeting Haifa or Tel Aviv, would signal an escalation, complicating the calculus for the Biden administration and bolstering the warmongering cries of Prime Minister Benjamin Netanyahu’s far-right allies.