TONY KARON

If Syria's showdown between the regime of President Bashar al-Assad and his opponents was following the trajectory of Libya's struggle against Muammar Gaddafi, this could be the moment that a U.N. no-fly zone became a matter of urgency. Syrian authorities reported on Monday that armed groups in the town of Jisr al-Shoghour in the north had attacked government buildings with machine guns and hand-grenades, killing 40 security personnel -- a number that quickly climbed to 120 in state TV broadcasts. That claim could not be verified in a situation from which foreign media are excluded, but even if it were a fabrication, it carries the same chilling implication: A Syrian cabinet minister warned that the regime would respond "decisively and with force", and state TV played a clip of a woman purporting to be hiding in a basement in the town from rampant gunmen, who pleaded with the authorities to send aircraft to bomb the town.

Opposition supporters reported that Monday's events followed days of clashes in the town, and some alleged that the scale of the violence was a sign that some of the regime's forces in the town had mutinied -- again, an unverifiable claim.

A similar rebellion in the same town in 1980 was crushed with scores of people killed, while in nearby  Hama, in 1982, the current President Assad's father, Hafez al-Assad, unleashed air power and artillery to crush the Islamist rebellion there by pulverizing the town and killing between 10,000 and 20,000 people. So when the Syrian authorities talk up the casualty count at the hands of an armed insurrection, that sounds ominously like p.r. preparation for a military operation that would put the lives of many civilians in Jisr al-Shoghour at risk.

And there have been growing signs in recent weeks that the violence unleashed by the armed forces to suppress civil disobedience has called forth a violent response from some opposition supporters, just as it did in Libya.

Still, even with human rights groups alleging that more than 1,000 people have already been killed in the uprising and the expectation of a bloodbath in Jisr al-Shoghour,  nobody has convened the U.N. Security Council to consider military action to restrain Assad from unleashing the power of his military on rebellious towns. Western powers have imposed some new sanctions. But they've refrained even from calling on Assad to step down, instead urging him to  democratize his country or get out of the way.

The reasoning behind this restraint -- and the reluctance of key section of the Syrian population to join the rebellion -- is not that the Assad regime is, from a strategic point of view, "too big to fail", as much as it is a fear of the consequences of it falling. Still, that  caution increasingly tested by the brutality of the crackdown.

There would, of course, be short-term strategic gains for the U.S., Israel and Saudi Arabia in seeing the fall of a regime that has served as the lynchpin of the Iran-led "Axis of Resistance" in the Levant, arming Hizballah in Lebanon and providing a headquarters for Hamas. But fear that if the regime did collapse in a violent showdown, its most likely successor would be the Muslim Brotherhood gives pause to the U.S., Israel and the Saudis.  They may not like Assad, but he's the proverbial devil they know, a man of predictable habit and therefore, by default, a bulwark o fa certain kind of stability. "Assad himself doesn't know how Syria will look at the end of this week or the next," Israeli military chief of staff Gen. Benny Gantz said Sunday. "The uncertainty is troubling him, and it is troubling us."

Then there's the sectarian and political calculus within Syria, which the Alawite and Christian minorities largely lined up behind the regime, and even the urban elites of the Sunni Arab majority that makes up the bulk of the rebellion ambivalent -- a factor that has largely spared the major cities, Damascus and Aleppo, from the uprising. The regime clearly still has a social base, and the rebellion has not drawn the whole population onto its side.

The regime, in fact, through its actions, may be effectively encouraging armed resistance -- and it may even be exaggerating its scale -- in order to present itself as the guarantor of stability against chaos. Armed confrontation would push the more extreme elements in the opposition to the fore, just as it would tilt the balance within the regime sharply in favor of hard-liners.

Unlike Gaddafi, who is almost universally loathed among foreign governments, Assad still has enough geopolitical backing to prevent any U.N. Security Council action against him, even if the Western powers were inclined to give him the heave-ho. (And currently, they're not.) Where the Libyan opposition had neighboring Egypt willing to facilitate their access to arms, Qatar willing to buy antitank weapons and European air forces willing to tilt the battlefield in their favor, no states are likely to back an armed rebellion in Syria. Still, Syria's rebels will get plenty of support and weaponry from Sunni insurgent communities in Iraq, and from allies in neighboring Lebanon.

The bitterness engendered by the regime's own violence may already have closed off reform by the regime as a path to restoring stability, yet the opposition forces are unlikely to muster the military means to topple Assad. They could, nonetheless, sustain a protracted insurgency in the hope that choking off the economy will eventually turn the urban elites against the regime, and prompt defections within the security forces. All of which portends a long, hot and morbid summer ahead.