Riddle Me This, Batman

The fates of Saddam Hussein and Moammar Khadaffi demonstrate the peril of opposing America without weapons of mass destruction (WMD) to fend us off, we are told. It's downright understandable that thug states like North Korea want nukes.

So in what world does it make sense to believe that Assad agreed to get rid of chemical weapons if it would risk his regime and very life? Isn't it likely that he views this agreement as a means to save his regime rather than make it vulnerable?

And in what world would Iran actually agree to abandon nuclear weapons programs in current negotiations? Weapons programs the Iranians don't even admit having, I'll add. Wouldn't that make Iran a potential victim of American attack?

Two thugs give up WMD programs and end up taking the long dirt nap because we went after them. And two others are willing to give up WMD (or insist they have none) in order to avoid taking the long dirt nap?

This nuance thing is obviously very difficult for me to grasp.