BEIRUT >> Since Israel launched its ground invasion of Lebanon, Israeli forces and Hezbollah militants have clashed along the border while the Lebanese army has largely stood on the sidelines.

It’s not the first time the national army has found itself watching war at home from the discomfiting position of bystander.

Lebanon’s widely beloved army is one of the few institutions that bridge the country’s sectarian and political divides. Several army commanders have become president, and the current commander, Gen. Joseph Aoun, is widely regarded as one of the front-runners to step in when the deadlocked parliament fills a two-year vacuum and names a president.

But with an aging arsenal and no air defenses, and battered by five years of economic crisis, the national army is ill-prepared to defend Lebanon against either aerial bombardment or a ground offensive by a well-equipped modern army like Israel’s.

The army is militarily overshadowed by Hezbollah. The Lebanese army has about 80,000 troops, with around 5,000 of them deployed in the south. Hezbollah has more than 100,000 fighters, according to the militant group’s late leader, Hassan Nasrallah. Its arsenal — built with support from Iran — is also more advanced.

Israeli forces and Hezbollah fighters have been clashing since Oct. 8, 2023, when the Lebanese militant group began firing rockets over the border in support of its ally, Hamas, in Gaza.

In recent weeks, Israel has conducted a major aerial bombardment of Lebanon and a ground invasion that it says aims to push Hezbollah back from the border and allow displaced residents of northern Israel to return.

As Israeli troops made their first forays across the border and Hezbollah responded with rocket fire, Lebanese soldiers withdrew from observation posts along the frontier and repositioned about 3 miles back.

So far, Israeli forces have not advanced that far. The only direct clashes between the two national armies were on Oct. 3, when Israeli tank fire hit a Lebanese army position in the area of Bint Jbeil, killing a soldier, and on Friday, when two soldiers were killed in an airstrike in the same area. The Lebanese army said it returned fire both times.

Lebanon’s army declined to comment on how it will react if Israeli ground forces advance farther.

Analysts familiar with the army’s workings said that, should the Israeli incursion reach the current army positions, Lebanese troops would put up a fight — but a limited one.

The army’s “natural and automatic mission is to defend Lebanon against any army that may enter Lebanese territory,” said former Lebanese Army Gen. Hassan Jouni. “Of course, if the Israeli enemy enters, it will defend, but within the available capabilities … without going to the point of recklessness or suicide.”

After the 2011 outbreak of civil war in neighboring Syria and the rise of the Islamic State militant group there, the Lebanese army saw a new influx of military aid. It successfully battled against IS on Lebanon’s border in 2017, although not alone — Hezbollah was simultaneously attacking the group on the other side of the border.

When Lebanon’s financial system and currency collapsed in 2019, the army took a hit. It had no budget to buy weapons and maintain its existing supplies, vehicles and aircraft. An average soldier’s salary is now worth around $220 per month, and many resorted to working second jobs. At one point, the United States and Qatar both gave a monthly subsidy for soldiers’ salaries.

The U.S. had been a primary funder of the Lebanese army before the crisis. It has given some $3 billion in military aid since 2006, according to the State Department, which said in a statement that it aims “to enable the Lebanese military to be a stabilizing force against regional threats” and “strengthen Lebanon’s sovereignty, secure its borders, counter internal threats, and disrupt terrorist facilitation.”