Being against guns in the hands of felons and the certifiably loony sounds like a good idea … one even the NRA, GOA and other pro-Constitution groups readily support. In fact, according to polls, NRA members would also support including known terrorists and those with strong terrorist ties (Major Nadal of Ft. Hood infamy had ten contacts with a fanatic Imam just prior to his shooting spree, for instance).
So what could be long with forbidding such people from purchasing firearms?
The devil, they say, is in the details.
Consider this thrust http://www.terrorgap.org/sign/terror-gap/
The problem with this proposal is noted in the article itself … there are no firm guidelines for who gets added to the list and who doesn’t. Moreover, if someone is wrongly added to the list (some congress critters, for example, have found themselves on the “No Fly” list), it is impossible to get off the list quickly enough to catch a plane (most tickets are non-refundable). It can take, literally, months of diligent effort and a fair amount of expense to get off that list and back on a commercial flight.
Coming soon, TSA inspections at bus and rail terminals. Already in place: roadblocks in border states.