In a speech last Sunday, Hizbollah’s secretary general, Hassan Nasrallah, affirmed that the rebels fighting the regime of President Bashar Al Assad could not defeat him. “The situation in Syria is getting more complicated,” he observed, “but anyone who thinks that the armed opposition is capable of [winning] the military battle is very mistaken.”

Nevertheless, Hizbollah appears to have factored such an eventuality into its political calculations in Lebanon. As the party contemplates the possibility of a future without a Syrian ally, it has fallen back on stopgap mechanisms to ensure that it can retain its weapons in a Lebanese society that is not eager to enter into another war with Israel. A new war would be far more devastating than that of 2006, with Hizbollah seen by many as a protection force for Iran’s nuclear programme.

The party has systematically rejected all calls for its disarmament, knowing that Tehran would regard such a step as betrayal. For an organisation with an organic link to Iran’s supreme leader, disarmament is unthinkable. And yet Sheikh Nasrallah realises that once Mr Al Assad goes, Hizbollah’s latitude to employ its weapons will be severely curtailed, given that the party will have lost the strategic depth that it enjoyed through its alliance with Syria.

These cannot be happy times for the party. Inside Lebanon, the Sunni community is mobilised, taking its strength from the uprising in Syria, which is about to remove a regime that has for decades marginalised Lebanon’s Sunnis. Indeed, the assassination of Rafik Hariri in 2005, for which the Syrian regime is widely believed to have been responsible in collaboration with Hizbollah, was interpreted in Lebanon as a way of preventing Hariri from emerging as a stronger Sunni leader after the 2005 elections.

Sunni factions were repeatedly humiliated by Hizbollah after Hariri’s killing. This culminated in the May 2008 military takeover of western Beirut, which forced the government to overturn decisions that Hizbollah had opposed. This led to a profound rift between the Shia community led by Hizbollah and Sunnis led by Hariri’s son, Saad Hariri.

Today, many Sunnis seek payback. While Mr Hariri has been out of Lebanon since April 2011, there are more extremist groups willing to stand up to Hizbollah. This is worrisome in that Hizbollah retains an extremely powerful military capacity. If defying the party carries the country into a sectarian civil war, it could be disastrous.

Hizbollah must also contend with a very different environment in the event of war with Israel. Facing domestic hostility, the party cannot easily impose a fresh conflict on a Lebanese population that refuses to see its country destroyed on Iran’s behalf. And without the presence of a friendly Syria, Hizbollah will find it difficult to rearm.

Moreover, there is some question whether the Shia community would want to be put through the wringer yet again, especially when outside Arab reconstruction aid is unlikely once the fighting ends.

Absent a domestic consensus behind the “resistance” option against Israel, and without Mr Al Assad on hand to rearm Hizbollah, the party’s ability to be an effective fighting force and carry Lebanon into war without worry of a backlash will disappear. And yet Hizbollah’s response to this reality has not been to embrace more modesty in its political ambitions; it has tried to strengthen its control over the Lebanese political system to safeguard its military capabilities.

This is the worst possible choice. Hizbollah intends to win parliamentary elections next year, along with its allies, and use this parliamentary majority to bring in a friendly president in 2014, when the mandate of President Michel Suleiman expires. Hizbollah would use the state to protect itself.

But this will not be easy. For Hizbollah to gain a majority, it will need a new election law that few of the major political actors approve. The party has pushed a law that would allocate parliamentary seats by proportional representation, assuming that it would lose far fewer seats than Mr Hariri’s coalition under such a formula.

However, such a law would spell defeat for a Hizbollah partner in government, the Druze leader Walid Jumblatt, who benefits from the current 1960 law, which is based on a winner-take-all system.

Mr Jumblatt has rejected the proposal for proportional representation, and he holds the balance in parliament. He can hand the majority to either Hizbollah or to the opposition March 14 coalition led by Mr Hariri. If Mr Jumblatt were to abandon Hizbollah’s coalition and call for a vote of no confidence, the government would collapse.

Hizbollah is not used to compromise, and is unlikely to reconsider its political strategy. However, the party is effectively setting itself up for a clash with Sunnis, at a moment when the alignment of regional forces is not to its advantage. Hizbollah is perhaps wagering that Christians’ anxieties about Sunni rule in Syria will rally them to its side. Yet few Christians approve of the party’s refusal to hand over its weapons to the state, and they certainly do not welcome the prospect of another war with Israel.

If Hizbollah feels that the way out of its dilemma is to forge blindly ahead against the majority of Lebanese opinion, it is mistaken. The party must step back and reconsider its options more lucidly. The future, once Mr Al Assad goes, will be very different from the past. Hizbollah must adapt, or be isolated in Lebanon and in Syria as a vestige of an Iranian agenda that many Lebanese will want to cancel.