Syria - again!!

Here we go again - should we bomb Syria?  Well in fact it's all water under the bridge, because we already have.  But should we have done?  There is little doubt that Assad is a nasty piece of work, but he is - at least nominally - the democratically elected president of his country, so should we be siding with the rebel forces seeking to overthrow him?  Did he carry out a gas attack on a rebel area the other day?  Maybe, or was it a put-up job?  The use of chemical weapons is illegal under international law, and this is our justification for attacking him.  I haven't seen any concrete proof that it was him - for all that I am being assured that such proof exists.  The saga continues...