Robert Fisk: Syria's conflict has crossed the border, and the ghost of Lebanon's civil war returns

Lebanese kidnappings 'stir memories of civil war'. Gulf Arabs flee Beirut. Lebanese Hezbollah sends 1,500 men to help Bashar al-Assad. Ex-Lebanese minister charged in Syria terror plot. The 'spill-over' – it's become the new cliché for Lebanon in the shadow of Syria's war – is fast becoming as dishonest as the lies invested in its promotion. So like gangrene, fear spreads across Lebanon when it needs a surgeon's dissection.

First, the kidnappings, 20 of them, all Sunni Muslims – Syrian businessmen, a Turk and a Saudi – near the airport road in Beirut, a highway controlled by the pro-Iranian, pro-Syrian and very much Shia Muslim Hezbollah. The Saudis, the Emiratis and Qatar have urged their citizens to flee the fleshpots of Beirut. And yes, kidnappings were fuel to the fire of the first weeks of the 1975-90 Lebanese civil war. But the reason for these abductions is a lot less clear.

We have to look at the case of one Hassan Selim Moqdad, for whom Beirut's latest hostages are held. A Lebanese Shia, he was seized by the Free Syrian Army inside Syria and videotaped babbling that he was a Hezbollah member, part of a 1,500-strong contingent of Hezbollah fighters sent to assist Assad. The Americans accused Hezbollah of assisting the Assad regime and thus further embittered those Lebanese Sunnis who hate Assad almost as much as they resent Hezbollah's MPs in the Lebanese parliament and its control of the Beirut government.

Now there happen to be about 17,000 Moqdads in Lebanon, all members of the same tribe but including not just Shia but Sunnis and Christian Orthodox as well. And Hassan Moqdad, far from arriving in Syria with a legion of Hezbollah fighters, had been staying there – this from his wife – since before the revolt began 18 months ago, because of financial problems in Lebanon. Hassan's money difficulties resolved, he was on his way home to Lebanon when he was kidnapped and transmogrified into a Hezbollah warrior. Hezbollah have denied that Moqdad was a member, just as they have insisted they've no militiamen fighting in Syria, a statement that may bear the merit of truth since Assad has plenty of plain-clothes Syrian gunmen without hiring any more from Lebanon.

The Hezbollah Party of God cannot deny that the 20 hostages in Beirut – all but six of whom had been released last night as Maher Moqdad (another of the famous 17,000) announced an end to such abductions – were all taken in an area which the government long ago effectively handed over to the party. In reality, however, the kidnappings symbolise not the power of Hezbollah but the utter impotence of the divided, self-abusive Lebanese government.

Maher Moqdad said one of the detained Syrians was an army lieutenant who wanted to join the rebels. Meanwhile, those same rebels claim to hold dozens of Iranian 'spies' captured on the Damascus airport road, although Iran says that all were visiting a shrine outside Damascus. But would Iranian secret agents really take a vulnerable bus to Damascus airport? The case is faintly similar to the six Iranian 'militiamen' captured in Homs who turned out to be legitimate power station workers.

Now that Michel Samaha, ex-minister, ex-MP, and Lebanese supporter of Assad, is charged with plotting to blow up Lebanese politicians on behalf of Syria's security major domo, General Ali Mamlouk, the 'terror conspiracy' – without a shred of evidence publicly revealed – has become fact. Like the mass of bank robberies around Beirut, the clan battles in the Bekaa Valley and the armed offensive against Lebanese troops trying to destroy the country's hashish fields, the whole shooting match doesn't exactly invite tourists and Gulf investors to sunny Beirut. Nor did it help when the Prime Minister, Najib Mikati, announced that the kidnappings "bring us back to the days of the painful (civil) war." Nor, I suppose, is there a surgeon who can put Lebanon together again.

Q&A: Why the war in Syria has crossed the border

Q. Why is the Syrian conflict spilling over the border?

A. The 17-month uprising is evolving into an increasingly sectarian civil war and many of the religious tensions on the ground are mirrored in Lebanon. Many Lebanese Shia Muslims support President Assad, as do the country's Alawites (the sect to which the Assad dynasty belongs). Lebanon also has a large population of Sunni Muslims who actively support the mostly Sunni uprising.

Q. Where does the Lebanese government stand?

A. Currently in government is the pro-Assad March 8 group, which is led by Hezbollah, a Shia militant group which along with Iran forms a key axis of support for Assad's regime. But the government must play a careful balancing act with regard to Syria so as not to inflame tensions.

Q. Why is politics so influenced by Syria?

A. Syrian peacekeepers moved into Lebanon soon after the outbreak of the country's own civil war in 1975, but became enmeshed in the conflict. It was only in 2005 – a full 15 years after the war ended – that Syrian troops pulled out. The withdrawal was triggered by mass street protests following the assassination of the Lebanese Prime Minister, Rafik Hariri, who wanted to roll back Syrian influence and whose death was blamed on Damascus. Few expect a war in Lebanon, but the longer the Syrian crisis drags on, the more destabilising it is for its smaller neighbour.

Loveday Morris