Where in the Constitution does it say that it has derivatives?
Lol!!! That is a funny question.
It doesn't. It's that simple.
Schlitz asked some questions concerning the BATF and they're good questions. The answer is long and usually boring... unless you're really interested in administrative law.
The BATFE is one of many agencies created by Congress. The "agency" is an interesting phenomenon(branch of law) that came into existence not too long after the civil war. Here's the reasoning...
Congress wants to regulate something but the House and Senate members are not really qualified to get into the details. So... Congress creates an agency under the executive branch and writes law within which the agency must operate. The agency is then populated with people that are supposedly "experts" in the field in which the agency has been given authority to regulate. In addition, congress gives the head of the agency the authority to promulgate "rules". Anyone see a problem here???
An agency promulgating rules under the executive branch is "legislating". Well, of course this issue was litigated way back and it was found that if the agency's rules remain within the confines of the power given to it by Congress then everything was ok... no separation of powers violation. In addition, there were due process issues that needed to be dealt with... hence the Administrative Procedures Act. There is one at the federal level and each state has adopted one similar.
So... if one wants to understand agency law, one would start with a good law outline on the topic AND the APA. It is important to note that it is the "agency" that has been used to grow the power of the executive branch. It behooves one to understand this branch of "law" in order to understand to what point "due process" has been stretched.