what is to stop the President from enacting an excutive order
Yes, I have thought about this in the past, but it seems unlikely of course I may eat my words one day.
However, I wonder how likely it might be from a legal and political standpoint to see departments or agencies within the Federal Government implement additional restrictions. For instance the Department of Homeland Security restricting and/or charging additional fees related to ammo sales. What about the Department of Health and Human Services implement a Trauma Center fee on firearms and ammo sales? These are things that might simply fly under the radar for the average citizen and have little negative political impact.
So, I’m not sure if the above are legitimate hypothetical examples, but could it happen from a legal standpoint?