The Syrian civil conflict could continue for several years - with Russian and Chinese political cover and military facilitation preventing the regime from being physically overrun, but with the majority of the population seeing the regime as illegitimate. The regime could however fall in weeks if there was an 'event' that swept it aside, such as another set of senior-level assassinations or high-level defections.
An announcement by the UK Foreign Secretary that financial and material support will be channelled to the opposition signals more loudly that the West's is siding with anti-regime groups both inside and outside the country. But is the UK and its allies, primarily France, Turkey and the USA, really ready for a regime collapse ? The opposition in Syria is understandably only loosely unified, and supported by a mix of countries with differing motives and interests. For example, do Saudi Arabia, France and Israel share the same vision for a future Syria ? Certainly they do not.
One can hope that Western security and military institutions have learned from Iraq and Afghanistan that regimes like Syria - somewhat artificial colonial creations - are fragile as nation-states. Such regimes survive by evolving a combination of brute force, hoarding of economic power internally and 'divide-and-bribe', with delicate balancing of external interests.
Syria itself has been assisted by the Soviets/Russians for decades - both militarily and in building its fear-based security state. The (militarily insignificant) Russian base at Tartus is of more benefit to Syria than to Russia, especially after President Putin unwisely made it a macho symbol of resurgent Russian power.
A consequence of these features is that Syria is another 'Humpty Dumpty state' - once it breaks it is extremely challenging to put it back together again, since age-old regional rivalries will result in different groups vying for power with different external backers - a recipe for a decade-long insurgency after the regime collapses, with echoes of Iraq and Afghanistan.
However the Western strategy, co-led by the UK, appears to be to work alongside Turkey and Gulf states, and wait for regime collapse, rather than cut a deal with Russia and China, and bringing in Gulf states and Syria's neighbours. One reason that this is dangerous, is that even Western policy is currently divided. Whilst the US State Dept is deploring civilian deaths and advocating democracy, US military and security officials, and Israel, are emphasising the risks of terrorism and the need to secure WMD inside Syria - creating two conflicting potential bases for external intervention. Attempting to dovetail the Syrian uprising with the 'war-on-terror' narrative, albeit tortuously, is likely to lead to conflicting Western aims.
Thus the UK is reduced to pursuing the only common denominator among its allies and anti-regime supporting countries - the fall of the Ba'athist Asad regime by whatever means. It is easy to see how the 'wait for the collapse' strategy of the UK is likely to lead to a long post-Asad tribal/sectarian conflict.
Alternatively, a deal needs to be prepared for a post-Asad Syria which will endure in the long run. This should probably include a new decentralised constitutional settlement with pluralism enshrined but exceptionalism ruled out, and a political system that does not exclude any one major grouping. It may include guarantees for the Russian base at Tartus, and a revival of freer trade arrangements with neighbours to ensure economic growth. Such an approach is, perhaps ironically, the most effective at ensuring that Syria is not a safe haven for non-state military actors.