I do not care for Bashar Al-Assad and, given his actions, he deserves to be hung by the rebels.  The question must be asked of you Mr President, if rebellion broke out in the USA would you not use force to suppress it? 
If half of the states, or say, every state west of the Mississippi decided they did not want you to be president would you just let them go?  Would you seek to divide our properties with them and let them go peaceably?    

Mr Obama, sir, if your answer is that half of our homeland's landmass could rebel against your administration, and you and your supporters would not resist by force of arms, then by all means attack Assad.  Go ahead and condemn him for what he is, and what the region he is in seems to demand of it's leaders.  (As much as I hate to say it Bibi Netanyahu was right when the said the middle East is not the Midwest1.  Nice guys don't last long there.)

Mr President if your answer deep down is that you too would use every available means to preserve the sovereign government of the United States of America no matter how unpopular it was with any segment or section of the country and nation then you should not attack Syria.  As much as we don't like it, for now, the Assad regime is the legitimate government of Syria.  

Look at the places where we have poked our fingers so far, Libya for example.  We toppled Ghadaffi after he gave up his Nuclear arms.  If he had been able to retaliate against say Marseille or Sicily  or Rome.... would we have messed with him?    Think of the object lesson we are giving the likes of Iran and North Korea.  Kim Jong Un can threaten our allies with nuclear weapons and we do nothing.  A brutal dictator fighting a bloody civil war uses a tactic that may be criminal and we attack.  Mr Kim has probably killed that many North Koreans just as brutally in the last month.  Why not attack him?   

If we attack when the honest answers are that you too might just go after rebels in our own land the same way then you are a hypocrite, and almost as immoral as the man you condemn.   If our answer as a country is that we only attack those that could never possibly hurt us, make us miss an episode of American Idol or even realize we are at war, then it makes us all look like a nation of bullies or worse.

You are my president and I am a loyal American.  Whatever you do I will support against the world.  Indeed if Syria's ally Russia decides to go as far as Nuclear retaliation if we should endanger their Mediterranean presence....I stand ready to be obliterated.  Please, don't place us in real danger of war, perhaps even Nuclear war, unless your conscious is totally clear about your own inclination to suppress rebellions. 

In short, Mr. President, don't be a hypocrite. 

For my part, I truly hope the rebels win.  There are ways we can help them and I'm sure we have covert operators on the ground helping them, just as Russia, Iran, and perhaps China have their operatives helping Syria.    I hope our proxy wins this war.  I hope the string Assad up by his gibblets I do.  My personal opinion for what little it is worth is that not one American life is worth risking here.  As bad as this is the same happens in numerous places all over the world.  Like everyone I pray for peace while war is often necessary. 

As a scientist even at this early stage some things I have done in the lab and on paper have had real world consequences.  My own experience on these things is not totally theoretical, as I have seen at least one defense company have a similar idea to my own and develop it into a test weapon that has been deployed on a limited basis.  Rather than pulling the trigger myself I may have, in some small way, helped make the trigger others will pull.  So, I too know, the horror of blood on my fingertips.   Please be careful in how much you bloody us.  

God Bless you and God bless America. 

1.) From memory Mr Netanyahu said something to this effect on an episode of This Week With David Brinkley back in the 1990's or it might have been without David Brinkley in the 2000's. 
http://www.washingtonpost.com/world/national-security/obama-set-to-speak...  (Where he took no questions)