Since the two sides faced off in the Second Lebanon War of 2006, both Hizballah and Israel have made extensive preparations for the next conflict. Hizballah has greatly expanded its rocket arsenal, has gained substantial tactical experience from fighting in Syria, and has greater access than ever to Iranian supplies; its likely plan is to overwhelm Israeli defenses with rocket and mortar fire—attacking targets not just in the north but throughout the country while conducting raids with ground troops. For its part, the IDF has studied the mistakes of the previous war and has made clear that the next one is likely to be catastrophic for Lebanon. Michael Eisenstadt and Jeffrey White explore the many likely scenarios that could lead to war, what that war would look like, and how the U.S. might be able to prevent it:

For Israel, a war of this magnitude and intensity will have major political, economic, and social consequences well beyond any military outcomes. It would mark the first time since the War of Independence that Israel, throughout its territory, would be a major battleground, with the population and infrastructure exposed to direct, and likely sustained, attack. Even given probable Israeli successes against Hizballah and improvements in civil defense, this would be a true test of the country’s resilience. . . .

Clearly, the overwhelming imperative for Washington is to prevent such a war in the first place. Yet U.S. policy in recent years may have made such a war more likely; by not providing more robust support to the non-Salafist opposition [to Bashar al-Assad] in Syria, the United States made the success of the Assad regime and its allies more likely. This may embolden them to build on their military successes and overreach—just as Hizballah’s success in forcing Israel out of Lebanon in 2000, and Hamas’s success in forcing Israel from Gaza in 2005, caused Hizballah and Hamas to engage in provocations that led to additional wars. Accordingly, Washington should quietly warn Hizballah, Iran, and Syria against actions that could lead to war, and signal that it will not restrain Israel if Hizballah acts recklessly or provocatively. . . .

In the event of war, the U.S. should provide Israel political cover and buy for it the time needed to strike a decisive blow against Hizballah—Iran’s foremost regional proxy. The United States should continue to provide Israel with the military means to sustain an intense and perhaps prolonged war against Hizballah. . . .

Finally, the United States should support termination of the conflict only when conditions for an enduring ceasefire have been met. Making clear to Hizballah that the United States will not seek a premature halt to a war that could make Hizballah—and the Assad regime—more vulnerable to their local Arab rivals and enemies may be the best way to prevent such a war in the first place.

Earlier this month, an operative working for, or in conjunction with, Hizballah snuck across the Israel-Lebanese border and planted a sophisticated explosive near the town of Megiddo, which killed a civilian when detonated. On Thursday, another Iranian proxy group launched a drone at a U.S. military base in Syria, killing a contractor and wounding five American soldiers. The former attack appears to be an attempt to change what Israeli officials and analysts call the “rules of the game”: the mutually understood redlines that keep the Jewish state and Hizballah from going to war. Nadav Pollak explains how he believes Jerusalem should respond:

Israel cannot stop at pointing fingers and issuing harsh statements. The Megiddo attack might have caused much more damage given the additional explosives and other weapons the terrorist was carrying; even the lone device detonated at Megiddo could have easily been used to destroy a larger target such as a bus. Moreover, Hizballah’s apparent effort to test (or shift) Jerusalem’s redlines on a dangerous frontier needs to be answered. If [the terrorist group’s leader Hassan] Nasrallah has misjudged Israel, then it is incumbent on Jerusalem to make this clear.

Unfortunately, the days of keeping the north quiet at any cost have passed, especially if Hizballah no longer believes Israel is willing to respond forcefully. The last time the organization perceived Israel to be weak was in 2006, and its resultant cross-border operations (e.g., kidnapping Israeli soldiers) led to a war that proved to be devastating, mostly to Lebanon. If Hizballah tries to challenge Israel again, Israel should be ready to take strong action such as targeting the group’s commanders and headquarters in Lebanon—even if this runs the risk of intense fire exchanges or war.

Relevant preparations for this option should include increased monitoring of Hizballah officials—overtly and covertly—and perhaps even the transfer of some military units to the north. Hizballah needs to know that Israel is no longer shying away from conflict, since this may be the only way of forcing the group to return to the old, accepted rules of the game and step down from the precipice of a war that it does not appear to want.