Across the Middle East, Saudi Arabia is attempting to push back against Iran. Now, after its defeat in Syria, struggles in Yemen, and mixed record in Iraq, Riyadh is set to make Lebanon the next front in its conflict with Tehran.

Saudi Arabia’s target in Lebanon is Hezbollah, the powerful Shiite party with an old and deep alliance with Iran. Thanks to Tehran’s generous and consistent financial and military assistance, Hezbollah has transformed into a formidable regional power—one that in recent years has cemented its dominance over Lebanon’s national security decisionmaking, bolstered its deterrence against Israel, helped save the Bashar al-Assad regime in Syria, and supported fellow Shiite militias in Bahrain, Iraq, and Yemen.

The Saudis see Hezbollah’s control of politics in Beirut as untenable. That is why, in a clear departure from past policy, they have decided to confront Hezbollah more actively by holding the Lebanese government responsible for the group’s regional adventurism—including in the Saudis’ own backyard in Yemen, where Hezbollah allegedly supports the Houthi rebels.

The first sign of punitive Saudi measures against Lebanon was the forced resignation of Prime Minister Saad Hariri on November 4, while Hariri was in Riyadh. The Saudis didn’t believe that Hariri, who had sought consensus with Hezbollah last year to ensure his own political survival, was willing or able to execute their new hardline policy on Hezbollah. So they compelled him to quit. But Saudi retribution might not stop here. Riyadh could also ramp up pressure on Hezbollah by pulling all Saudi deposits from Lebanese banks and expelling Lebanese nationals from Saudi territory, both of which would be detrimental to the country’s financial stability. Riyadh may assume that an internal crisis in Lebanon will distract Hezbollah, preventing it from expanding and deepening its involvement in other battlefields across the region.

A major disruption of the status quo in Lebanon will expand the arc of crisis and chaos across the region.

The Saudis have every reason to be concerned about Hezbollah’s activities in Lebanon, Yemen, and elsewhere. There is no question that the group’s lack of accountability to the Lebanese state, total disregard for Lebanese sovereignty, and cache of weapons (which it has used against both domestic and foreign foes) will continue to impede Lebanon’s state-building project and threaten the security of several of the United States’ regional partners, including Israel. But causing political ruin and economic collapse in Lebanon as a way to weaken Hezbollah, as the Saudis seem intent on doing, is in nobody’s interest.

U.S. President Donald Trump’s full embrace of the new Saudi leadership, represented by King Salman and his son Crown Prince Mohammed bin Salman, has enabled the kingdom to stake out a bold position vis-a-vis Iran and pursue its risky gamble in Lebanon. But it seems that other senior members of the administration have privately but sternly urged their Saudi counterparts in Washington to back off on Lebanon and refrain from using the country as a venue for their proxy confrontation with Iran. If such reports are accurate, these officials were absolutely right in doing so. But it is unclear whether Riyadh will listen.

There are three reasons why the United States should put a firm brake on Riyadh’s plans in Lebanon: First, the Saudis are likely to alienate their own Lebanese allies and strengthen Hezbollah; second, the costs to the United States of destabilizing Lebanon are much greater than the benefits to be gained from an ill-conceived fight with Hezbollah; and third, there are better ways to undermine Hezbollah without hurting Lebanon as a whole.

Hariri at the Élysée Palace in Paris, November 2017. Benoit Tessier / Reuters

Saudi Arabia’s new Lebanon policy has already generated a ton of resentment among the country’s Sunnis—the one community that is supposed to be most supportive of Riyadh. By strong-arming and humiliating their leader so publicly, Saudi Arabia has alienated many Lebanese Sunnis. Their love of country is stronger than their hatred of Hezbollah. Moreover, they, like all Lebanese, are deeply concerned about their living conditions and economic fortunes, and fear what would happen should Saudi Arabia start applying financial sanctions indiscriminately.

Political volatility and financial hardship, moreover, might distract Hezbollah but won’t necessarily weaken it. The group is perfectly capable of finding a replacement for Hariri, and even if relations deteriorate between Sunnis and Shiites in Lebanon, Hezbollah has the guns to silence its critics—more guns, in fact, than the country’s armed forces. One must remember that Hezbollah was born in the midst of the most violent phase of the country’s civil war in the early 1980s. It thrives in chaos and over time has mastered the art of survival. Hezbollah is not untouchable, but it is dominant partly because its local adversaries are weak and divided.

A major disruption of the status quo in Lebanon will expand the arc of crisis and chaos across the region, likely benefiting the United States’ enemies, including Iran, the Islamic State (ISIS), and al-Qaeda. The United States has spent a ton of treasure and political capital to kick ISIS out of Iraq and Syria. The last thing it wants is a broken state in Lebanon that would give ISIS an opportunity to regroup while providing fertile ground for other extremist movements.

Despite its profound dysfunction, moreover, Lebanon does offer a model of sectarian coexistence that could be enormously useful for countries such as Iraq, Syria, and Yemen, which have been wracked by civil war. Lebanon’s unique political experiment and religious openness are the most potent weapons against further radicalization in the Middle East. All of this is no doubt worth preserving.

Finally, there are better ways to accomplish Riyadh’s goal of weakening Hezbollah. The Saudis would be better off working with the United States to enact tougher and more pointed financial sanctions against Hezbollah instead of trying to tank the Lebanese economy, which is already struggling to deal with some 1.5 million Syrian refugees in a country of barely six million. The Saudis could also financially support their allies in Lebanon’s parliamentary elections, currently scheduled for March 2018, to help reduce Hezbollah’s political influence.

Lebanon is both too fragmented and too precious to be used as a proxy in Riyadh’s strategic competition with Tehran. This strategy has been tried before by Israel, with help from the United States, on multiple occasions (most recently in 2006), and every single time it has led to disaster and further weakening of the country. Saudi—and U.S.—interests would be better served by learning from that history.