Institutions get designed around their mandate. If you're trying to run a school system you wouldn't invent a court. If you were trying to deal with violations of law you wouldn't create a school board.
The federal government's mandate was to manage issues that arise between states and each other, between states and other countries and to a lesser extent, to prevent the states from violating the rights of their inhabitants and its architecture reflects that mandate. Over the years the federal government has expanded in scope far beyond the types of issues it was designed with the intent of managing. Expecting that system to provide decisive action on issues that are outside of what the system was designed for is unrealistic.