Even if Bashar Al Assad loses in a war that drags on for years, the log term effects on Syria and the rest of the Middle East could be disastrous. The world cannot wait and watch while that happens.
Without intervention, Syria will be dragged down with Assad
The summer has been sweltering in Beirut after a strike by electricity workers brought unpredictable power cuts. All along the city's Corniche this week, late into the cooler night as people stay up during Ramadan, families have been smoking shisha, playing cards and strolling.
Among them are many new arrivals - Syrians refugees. Small children, thin and ragged, look up at strangers and murmur, while the more energetic boys dart between cars and tap on windows. The most heartbreaking sight is of older women, many in surprisingly elegant clothing, eyes downcast, forced to beg in an unfamiliar city.
Syrian children have been enrolling in Lebanese schools, and there are stories of middle-class families returning to Damascus, unable to afford Lebanon's skyrocketing rents. Some say they will leave their families in Lebanon for safety; others that they will seek to move to the Gulf states or Europe.
Once Syrians relocate, it will be difficult to bring them back. A small piece of Syria's stability will go with them. The bonds that hold society together are fracturing. They will need time to rebuild.
But time is not on the side of the uprising. As the international community scrambles to form a response following the failure of the Annan mission, the Syrian regime pounds its own cities. The Free Syrian Army still fights, but they are a lightly armed militia facing a regime with tanks and combat aircraft.
With time, President Bashar Al Assad may still turn the tide of the uprising, never re-establishing full control, but doing enough to prolong the war so Syria crumbles beneath him. Even if he loses in a war that drags on for years, it would destroy the country with knock-on effects across the Middle East.
The world cannot wait and watch while that happens. It is right that foreign powers intervene in Syria, and it is right that intervention has already begun.
Arguments against intervention rest on three main premises: that it will be difficult politically (in a US election year) and militarily (Syria's air defences are formidable); that regime collapse would lead to a wave of instability across the region; and, in a related point, that sectarian bloodshed would follow the end of the Assad regime.
Start with the last two. Both arguments actually make the case for intervention now. As is clear from the situation in Lebanon, instability is already spreading beyond Syria's borders. The longer the conflict continues, the more the regional mosaic will be damaged, and the harder it will be to piece it back together.
The same argument applies to sectarian divisions. Every month the uprising continues, the more probable it is that further bloodshed will continue after the regime's fall. In Iraq, there was no inevitability of sectarian bloodshed after Saddam Hussein. Specific political decisions led to the subsequent violence. Too much instability for too long created those conditions. When the dome of the Al Askari mosque in Samarra was destroyed in 2006, the tinder was already dry.
That is not yet the situation in Syria. There is still a willingness to forgive. But the longer the conflict burns, the quicker it will evaporate.
Intervention will be difficult - that is not an excuse for inaction, but merely a warning. Intervention could be implemented in stages. The strength and resilience of the Free Syrian Army, which has already scored a spectacular strike against the regime, should not be underestimated. Intervention should be aimed at giving the rebels the tools to topple the regime themselves.
This intervention is already underway. News agencies have reported that a base has been set up in the city of Adana, in southern Turkey, near a joint Turkish-US air-force base, from where the two countries and Arab allies are assisting the rebels. At the same time, Reuters news agency reports, US President Barack Obama has signed an order authorising US support - although not military support - for the rebels.
This is a good start. Covert US and Arab support could be the push that tips the balance. For now, a no-fly zone would be premature, but the option ratchets up pressure on the regime. Before Arab countries, Turkey or the United States put combat planes in the air, what is needed are more boots on the ground. Foreign special forces are reportedly already on the ground in Syria. Logistical assistance, backed by satellite and other intelligence, remains the best way to help the rebels to end the current stalemate.
Those who argue against intervention in Syria are behind the curve. It is has already begun. The task now must be to carefully increase pressure to end the fighting in a way that preserves as much of Syria's infrastructure, institutions and human resources as possible.
There is no good solution in Syria today. What comes after the Assad regime and what leadership will emerges from the opposition are still unknown - and cause for legitimate concern. But political uncertainty should not obscure the humanitarian situation on the ground. The Assad regime is crumbling. If it is not brought to a swift end, it will bury the whole country as it collapses.
Follow on Twitter: Ÿ Tomorrow Hassan Hassan argues that intervention will do more harm than good