When the Israel-Hezbollah conflict in Lebanon was threatening to unravel the U.S.-Iran peace deal, President Trump repeatedly floated an idea that took many in the region by surprise.

Neighboring Syria, whose relatively new government is no friend to Hezbollah, could help subdue the Iran-backed Lebanese militia.

The proposal revived bitter memories in Lebanon, which the Syrian military occupied for nearly three decades. It also baffled Syrians, whose government has made clear over and over again that it has no interest in meddling in its neighbors’ affairs or entering into more wars.

President Ahmed al-Sharaa reiterated that stance last week, rebuffing the notion that his U.S.-allied government was preparing to intervene militarily in Lebanon.

A solution for Lebanon that involves Syria “does not mean war and does not mean the old image of Syrian tutelage over Lebanon under the former regime,” Mr. al-Sharaa said in an interview on al-Mashhad TV, a Pan-Arab network based in Dubai. “We tried war, and we do not wish it on anyone.”

His stance reflects the geopolitical sea change that came with the toppling of President Bashar al-Assad by Mr. al-Sharaa’s rebel coalition in December 2024.

For decades under the Assad regime, Syria was a close ally of Iran and by extension its Lebanese proxy militia, Hezbollah. The country served as the main overland route through which Iran supplied Hezbollah with weapons and funds. In return, Hezbollah deployed its fighters to help the Assad government fight rebel forces during Syria’s nearly 14-year civil war.

The ouster of Mr. al-Assad changed that.

The rebels whom Hezbollah had spent years fighting in Syria were suddenly in power in Damascus. The group’s land bridge to its patron Iran was severed. And its most powerful ally aside from Tehran was gone.

Since taking power, Mr. al-Sharaa’s government has made it clear that it is no friend to Iran or its proxies in the region, including Hezbollah.

The Syrian Ministry of Interior has arrested people it suspects of being connected to Hezbollah, cracked down on cross-border smuggling and accused Hezbollah-linked groups of plotting attacks inside Syria. Hezbollah has denied those claims.

That animosity has probably contributed to the idea in Mr. Trump’s orbit of a Syrian intervention in Lebanon, analysts say. Mr. Trump has floated the idea repeatedly over the past two weeks as his frustration with Israel’s war in Lebanon has grown.

“I’d like to see a more surgical attack on Hezbollah,” Mr. Trump said in an interview with NBC News this month, adding, “We can help them with that, or we can recommend Syria.”

“Israel is fighting Hezbollah too long, and too many people are being killed,” Mr. Trump said at the Group of 7 summit in France days later, adding that “if Israel can’t do the job without killing everyone else,” Syria will.

The suggestion was Mr. Trump’s latest vote of confidence in Mr. al-Sharaa’s government. Over the past year, the Syrian government has cultivated close ties with the United States, winning sanctions relief and praise from Mr. Trump.

The United States also has close ties to Lebanon and is a leading supplier of military aid to the country.

“The U.S. is likely pressuring Syria into getting involved in Lebanon because successive U.S. administrations have viewed Lebanon and Syria as part of the same Levant file,” said Lina Khatib, a Middle East and North Africa fellow at Chatham House, a think tank. “And because both those countries’ governments are dependent on the U.S. politically.”

The proposal has raised alarm across the region.

Within Lebanon, it has stoked fears of repeating recent history. Syrian forces entered Lebanon in 1976 as part of an Arab peacekeeping force soon after the start of the Lebanese civil war. Syria subsequently occupied Lebanon for 29 years, during which it dominated Lebanon’s political and economic life. Its last forces pulled out in 2005, leaving behind anger and bitterness over its human rights abuses and interference in the country’s politics.

Syrian intervention could also expand the country’s influence in the region and by extension the influence of its ally Turkey — a prospect that analysts say could alarm Israel, which sees Turkey as a foe.

Even for Syria, the notion of fighting an old enemy in neighboring Lebanon has little appeal as its government works to consolidate its power and authority within its borders.

Having emerged from a brutal and fractious civil conflict, the country and its leaders are still struggling to rebuild both homes and infrastructure and a society divided along numerous fault lines, including sectarian ones.

“Getting Syria to intervene in Lebanon to help disarm Hezbollah is a recipe for destabilization in both countries,” Ms. Khatib said. “If Syrian troops enter Lebanon, this will spark sectarian tensions in the country and undermine the authority of the Lebanese government.”

Hezbollah might also try to retaliate by stirring trouble inside Syria, she added.

“Even if the U.S. pressures Syria, the last thing Syria wants is to be juggling domestic and foreign wars at once when the Syrian state is already struggling to exert its security and military authority within Syria,” Ms. Khatib said.

Reham Mourshed contributed reporting from Damascus, Syria.