Given that about 130,000 people have died in Syria over the last two years, there is something superficially galling about the focus on the recent deaths of about 1300 people in a chemical weapons attack in Damascus.
The feasibility of intervention was greater two years ago. I know that there is little public appetite for it in the west but inaction has empowered the radical jihadists. This has made it harder to achieve either a political settlement or a pluralist Syria which would protect the rights of minorities such as the Kurds, the Christians and the Alawites.
It has also emboldened Assad whose initial toying with reform has been replaced by unbounded terror and, as far as anyone can tell, has prompted the use of chemical weapons on a scale similar to the use of such weapons at Halabja in Iraqi Kurdistan 25 years ago. The British Foreign Secretary William Hague has added his voice to those who think that Assad carried out such an attack.
The initial American response to its then de facto Iraqi ally over Halabja in 1988 was a disgrace. The attack took place towards the end of the war between Iraq and Iran and the State Department initially muddied the waters by insisting that Iran had carried out the attacks.
If Saddam hadn't incurred the wrath of the west by invading Kuwait - although it can be argued that western ambiguity helped persuade him he could get away with it - then it is likely that Saddam would have thought he was able to continue his genocidal campaign against the Kurds. Fortunately, he was forced out of Kurdistan which was protected by a no-fly zone.
If Assad is not punished for going beyond conventional munitions, it reduces the thresholds in Syria and elsewhere. Given that President Obama has warned that the use of chemical weapons is a red line and a "game-changer" which would change the calculus of action, it is imperative that action is now taken.
The respected American foreign policy expert Richard Haass rightly writes in the FT that "It will be a very different 21st century if weapons of mass destruction - whether they are chemical, biological or nuclear - come to be seen as just another type of weapon. There needs to be a robust taboo surrounding their use. Any leader must know that a decision to deploy them will sacrifice sovereign immunity and result in many in the world accepting nothing less than ousting and arrest."
Haass is also concerned about American credibility, not least in relation to its commitments to stop Iran from acquiring nuclear weapons: "A president cannot afford to be selective when it comes to drawing red lines if he wants them to be respected."
Haass understands the reluctance to intervene but suggests that the way to balance both the need to respond and the need for restraint is through launching launch cruise missile strikes against select targets: "anything associated with chemical weapons, command and control sites, and airfields used by government forces." He combines this with supplying those opposition forces deemed politically acceptable with significant numbers of anti-air and anti-armour capabilities.
Clearly, it would be better if international action were possible with the support or at least non-opposition of Security Council members, China and Russia but if that is not possible then America should take its own action in a new coalition of the willing, including the UK.
Failure to take such action will almost certainly condemn more Syrians to the horrible and lingering death of chemical weapons as well as conventional munitions. It will increase the possibility that chemical, biological and even nuclear weapons come to be seen as acceptable in the future. The stakes are huge and, however difficult it is, President Obama must take the lead.