Why should action be taken because chemical weapons were used?

Because that is the long established accepted response to the use of such weapons. During the "Cold War" NATO renounced the use of such weapons, the Soviets and their Warsaw Pact allies did not. The latter were told in no uncertain terms that use by them of chemical or biological weapons would immediately result in tactical nuclear strikes - this "accepted" response was relayed to Saddam Hussein by the Soviets in 1990 in the run up to Desert Storm and it was Saddam's fear of a tactical nuclear response that stopped him from using chemical weapons in 1991 when we knew for certain that he definitely did possess them and had the means to deliver them.

The UN inspectors went into Syria with a fairly specific and time limited mandate. In this respect the weapons inspectors job in Syria cannot be compared to the task set for either UNSCOM or UNMOVIC in Iraq. The UN inspectors have completed their task in Syria, they have inspected the sites of alleged chemical attacks inside the country and samples taken are currently being analysed. Unlike Iraq the weapons inspectors who have just returned from Syria have got all the information they need and within the next few weeks they will issue at least a preliminary report indicating:

1) What was used
2) How it was weaponised
3) How it was delivered

From the above will come the best indication of "who dunnit".

Chemical weapons used on the 21st August in Damascus - eliciting no strong response provides encouragement to any "rogue regime" with its back to the wall - you do not have to worry about any response by the USA, or whoever, spurring terrorist groups into using the stuff, if they had possessed any they would have used it long before now without blinking an eye.

Jom, insists that the sodium fluoride that Syria was sold from the UK last January was immediately used to manufacture the Sarin Gas used in the attack on the 21st August - he states this without producing any evidence to support his contention - and he expects to be universally believed, purely on his say so - sorry not convinced. It would be interesting to know how much sodium fluoride is normally purchased by Syria, it would be interesting to know how much is used for water purification and the dozens of other perfectly rational innocent uses of the chemical. It would then be interesting to see how quantities match up, before leaping to the conclusions reached by Jom "the impartial".

Kerry has talked of and described in detail the "trail" of evidence that the US has gathered in the 72 hours leading up to the attack:

a) Increased activity at a known chemical weapons storage site
b) Transport between that storage site and known Syrian Army bases
c) Intercepted communications and telephone conversations between the Assad regime, the storage site and the Syrian Army
d) The subsequent launching of rockets and artillery fire from areas under the control of the Assad regime by the Syrian Army.

By waiting until the UN's weapons inspectors deliver their preliminary findings, the US Government can specify what it was that was transported, they can state what all those conversations were about. They can completely explode the myth being promoted by Russia that Assad did not use chemical weapons against his own people.

Now why would the Assad regime resort to using such weapons? I can think of a number of reasons both tactically and strategically as to why he would risk using them, especially if at the end of all this he expects to remain in power, which I am sure he does - and none of those Assad regime goals will be derailed by the USA launching a few cruise missiles into "selected" targets in Syria.

World War Three will not be started in order to save President Bashar al-Assad in Syria - basically he is not worth it to either Russia or China, because they know full well that at the moment neither, even combined, are strong enough to defeat the USA if push came to shove, they simply have got far too much to lose.