Congress delegated rulemaking authority to the executive branch in a number of areas and has the power to un-delegate it, but has chosen to not exercise that po

Congress delegated rulemaking authority to the executive branch in a number of areas and has the power to un-delegate it, but has chosen to not exercise that power. They don't, in part, because that would create a lot of work for Congress, which would interfere with Congress' ability to solicit and deliver on bribes.