There is NO smoking gun documenting that Assad used chemical weapons. Of course that does not mean that he did not use them. Due process requires that this issue be investigated by an independent third party. The Syrian rebels may well have been the ones who discharged the chemical weapons.
The resolution of this question is critical as the news media, politicians, and pundits comment and offer advice based on the unproven assumption that it was Assad who used the chemical weapons. Consequently, those who support a military strike against Syria claim that we must blindly stand behind our President and that we have a moral obligation to teach Assad a "lesson".
If Assad did not use chemical weapons, these concerns evaporate. In fact, why should we follow a President based on faulty evidence and shouldn't we then teach the rebels a "lesson" if they were the ones to use the chemical weapons?
When the opportunity arises; request the politicians, media, and pundits to pursue an investigation as to who actually used the chemical weapons.