First I want to make it clear that all gun transactions should have a background check conducted so that we do not end up with another unnecessary killing of any kind. As for the stance of the current politicians Clinton is the worst of the bunch and should be avoided at all cost! When Clinton came to my work place I spoke with the people protecting her(Secret Service)and was informed that she absolutely hates guns!
As for Obama... anyone that stands against concealed carry is not to be trusted either! I am glad that he supports retired military/police carry but we still need to have concealed carry to protect us from the evil people in the world.
McCain I am uncertain on but have a bad feeling about him when it comes to the Second Amendment.
Ultimately we need to consider that the next president will be appointing at least one more Supreme Court justice in addition to several lower court justices.
The Supremem Court ultimately decides how the Constitution and Bill of Rights is intrepreted and that is where we need to be worried...
Clinton will most definitely appoint someone that will align themselves with the gun control fans and I believe that Obama will do the same. As for McCain again I do not trust him and want to do more research on his gun rights voting recording but at this point he should be treated the same as Clinton/Obama.