The sudden resignation of Lebanese Prime Minister Saad Hariri has plunged Lebanon into political uncertainty and raised fears that this tiny Mediterranean country is going to be dragged into the center of the burgeoning and at times violent regional confrontation between Sunni Saudi Arabia and Shiite Iran.

Saudi Arabia, reacting to the increasing influence the Islamic Republic wields in Lebanon, Syria, and Iraq, has in recent months steadily escalated its hostile rhetoric toward Iran.

And in announcing his shock resignation Saturday in Riyadh, to which he appeared to have been summoned, Mr. Hariri lashed out at Iran and its powerful Lebanese ally Hezbollah in an uncharacteristically public fashion.

His resignation seems to signal that a bullish Saudi Arabia, buoyed by the Trump administration’s anti-Iran stance, is no longer willing to allow its Lebanese ally to compromise with Hezbollah, an arrangement which over the past 12 months has brought some rare stability to Lebanon.

It is difficult to see what gains Saudi Arabia can leverage out of Hariri’s resignation that would put the Shiite organization Hezbollah, a key battlefield supporter of Syrian President Bashar al-Assad and the dominant political and military force in Lebanon, in a bind.

But the move, which would appear to sacrifice Hariri’s political standing, creates potential political and economic difficulties that could shatter Lebanon’s hard-won stability of the past year, a precious commodity in a country that has been buffeted by political and sectarian strife for decades.

“This does not reflect well on Hariri. It does not look like the first, second, and third orders of effect have been thought through,” says Randa Slim, a Hezbollah expert and director of a conflict resolution program at the Middle East Institute in Washington. “What will Hariri and Saudi Arabia do next? A resignation will not force Hezbollah to change its posture in Lebanon, Syria and regionally.… What concessions does he want to exact from Hezbollah and their Lebanese allies on matters dealing with domestic affairs?”

Hariri headed to Riyadh on Friday for an unscheduled visit, having been in the Saudi capital only three days earlier. The next morning, he announced his resignation in a live broadcast on the Saudi-owned Al-Arabiya network.

Assassination plot?

Despite all the compromises he had made, he said, he feared there was a plot to assassinate him, a fate that befell his father, Rafik, who was killed in a massive explosion in downtown Beirut in February 2005.

“We live in an atmosphere that prevailed before the assassination of martyr Premier Rafik Hariri, and I sensed what is being woven in secret to target my life,” he said.

Al-Arabiya subsequently reported that an attempt had been made to target Hariri’s motorcade in Beirut. The claim has been met with general bewilderment and skepticism in Beirut. The Lebanese police and army both issued statements saying they were unaware of an assassination plot against Hariri.

Looking uncomfortable and reading from a sheet of paper, Hariri said Iran “sows sedition, devastation, and destruction in any place it settles” and its hand would be “cut” in the region. Hezbollah, he added, “has unfortunately managed to impose a fait accompli in Lebanon by the force of its weapons, which it alleges is a resistance weapon [against Israel]. This weapon is directed against our Syrian and Yemeni brothers, in addition to the Lebanese.”

Hariri’s allies in Lebanon and members of his Future Movement parliamentary block were as stunned as everyone else at the surprise development, having had no forewarning. But analysts say that the Saudis had tired of Hariri turning the other cheek to Hezbollah.

“The Saudis are not satisfied politically with the status quo in Lebanon,” says Imad Salamey, associate professor of political science at the Lebanese American University in Beirut. “Given the fact that Hezbollah is participating in government … and at the same time it is able to defy the Saudi agenda by its continuous and various interventions in the region ... the Saudis feel that Hariri was providing Hezbollah legitimacy despite, from the Saudi view, Hezbollah’s arrogance and … the continuous expansion of Iran in the region.”

What Lebanon loses

The resignation has shattered a shaky consensus over the past year that had seen Lebanon regain a semblance of political normality. A two-and-a-half-year deadlock over the Lebanese presidency ended in October 2016 when Hariri finally agreed to nominate Hezbollah’s candidate, Michel Aoun, a Maronite Christian (as all Lebanese presidents are required to be). In return, Hariri won the premiership and a government was formed within a month.

Since then, the government and parliament were able to adopt a new electoral law for parliamentary polls scheduled for May 2018, which will be the first since 2009. A state budget was agreed upon, the first for 12 years, and legislation was passed that revived long-stalled moves to explore for oil and gas in Lebanon’s offshore waters.

In July and August, separate offensives by Hezbollah and the Lebanese army drove out several hundred militants belonging to the Islamic State and other groups from a pocket of northeast Lebanon, which has allowed the state to bring stability back to an area that had been lawless since 2014.

Hariri took some flak from his support base within the Sunni community for his cooperation with Hezbollah, which holds two seats in the government. Although Hariri is politically opposed to Hezbollah, he repeatedly stated that his actions were for the benefit of stability in Lebanon and that confronting the powerful Shiite group would only cause strife. And that is what makes his surprise, and fiery-worded, resignation Saturday all the more surprising.

A senior source in Hariri’s Future Movement justifies the resignation by saying that Hezbollah had never shown the same willingness to compromise as shown by the prime minister, the alleged assassination plot being the final straw. The source cites Hezbollah’s interventions in Syria and Iraq and its efforts to normalize relations with Mr. Assad’s regime, against Hariri’s wishes, and criticism of Gulf countries, including Saudi Arabia.

“Hezbollah never ceased to attack Lebanon’s interests in having good relations with Saudi Arabia, the UAE [United Arab Emirates], Kuwait and the region; never ceased to put Lebanon in harm’s way by putting it at odds with the international community, with the Americans, with Lebanon’s friends; never ceased for one second,” says the source, requesting anonymity in order to speak frankly.

Hezbollah responds

Sunday evening, Hezbollah leader Sheikh Hassan Nasrallah called for “calm and patience” while apparently absolving Hariri of blame for the resignation, pinning it squarely on Saudi Arabia instead.

“We will not comment on the political content [of Hariri’s resignation speech], which was very tough and included many dangerous points, but we will not comment because we believe it was a Saudi text and a Saudi statement,” Mr. Nasrallah said in a televised speech.

The non-combative tone of Nasrallah’s speech may help ease worries of street clashes between rival supporters of Hezbollah and Hariri and suggests that the Iran-backed party does not seek an escalation over the crisis.

“Hezbollah doesn’t intend to become more confrontational with the Saudis than it already is,” says Ali Rizk, a Lebanese political analyst close to Hezbollah. “They have more than one thing to keep them preoccupied – you have Yemen, you have Syria, you have the Israeli threats … so I don’t think they want to deteriorate the local internal situation.”

But in what some in the region interpreted as a response to Hariri’s resignation and his harsh rhetoric against Iran, a ballistic missile was launched toward Riyadh Saturday evening from Houthi rebel territory in Yemen. The missile was intercepted by a Saudi anti-missile system close to the city’s King Khaled airport, causing alarm but no casualties.

Saudi Arabia initially blamed Iran for the attack, prompting the Iranian Foreign Ministry to describe the Saudi accusation as “unjust, irresponsible, destructive, and provocative.” Monday the Saudis went a step further, saying Hezbollah operatives in Yemen had fired the missile in collusion with the Iranians.

Hezbollah's 'war'

As part of the heightened Saudi rhetoric of late, Thamer al-Sabhan, the Saudi minister for Gulf Affairs who has been particularly vocal in lambasting Iran and Hezbollah via Twitter, criticized the Lebanese government on October 29 for its “silence” on what he called Hezbollah’s “war” against Saudi Arabia. The next day, he doubled down on his rhetoric, saying that Hezbollah must be toppled and that the “coming developments will definitely be astonishing.”

On Oct. 31, Hariri travelled to Riyadh, where he met with Crown Prince Mohammed bin Salman and Mr. Sabhan. Although details of the meetings were not revealed, Hariri returned to Beirut amid reports that he had persuaded the Saudi leadership to grant him more flexibility in dealing with Hezbollah.

On Friday, Hariri met in Beirut with Ali Akbar Velayati, Iran’s senior adviser on international affairs. Mr. Velayati noted his “good, positive and constructive” conversation with the Lebanese premier, adding “Iranian-Lebanese relations are always constructive and Iran always supports and protects Lebanese independence, force, and government.” Perhaps that comment stung the Saudi leadership, because within hours, Hariri was back in Riyadh on an unscheduled visit, and the next morning he delivered his shock resignation.

On Monday, Sabhan released another, ominous, tweet, saying “Lebanon, after the resignation, will never be as it was before.”

“We will not allow it – in any form – to be a platform for terrorism against our countries,” he wrote, “and it’s in the hands of [Lebanese] leaders to allow for a state of terrorism or peace.”