One of the things Obama campaigned on, was that as far as gun-control went, he said he wasn't for "one-size-fits-all" solutions: aka let each area define its own standards.
Well, how about we turn it around on him? HR 45 would impose nationwide personal licensing and gun registration, isn''t that exactly the opposite of what he campaigned for?
Personally, I don't think it will get traction. But let's suppose it did. He could be hoisted by his own petard.