There are several such in the form of overlapping and shared responsibilities across a variety Executive Branch Departments and Agencies.
Three that come to mind are anti-trust enforcement, which is shared between DoJ and FTC, among others; environmental concerns, which are shared among EPA, Interior, Energy, and DoJ among others; and energy development/production, which is shared among Interior, Energy, and EPA, among others.
There are many more.
What DOGE needs to recommend and what President Donald Trump (R) and Congress (because much of this must be done statutorily) need to do is designate one Department/Agency in each of those areas as the Responsible Department/Agency, remove all responsibility, including the Civil Service positions and authority to consult “outside experts” from the other entities, and return the associated personnel to the private sector (no reallocating them to other areas of the Federal government). This both streamlines government and reduces its size by eliminating the jobs altogether.
With regard to DoJ in particular, that Department’s role in any of this should be limited to bringing cases to court; those personnel are enforcers of existing law, not definers of what the law is or should be (though, in the latter case, they certainly can recommend to Congress).
Another target rich environment for DOGE is entirely within the Pentagon. Defense systems development and acquisition is entirely too byzantine, and that labyrinth contributes in large part to the excessive amount of time—years—it takes the Pentagon to develop a system from an initial idea and to the excessive amount of time—more years—to acquire the systems in operationally useful numbers, once a decision to acquire is made. Those interminable delays also vastly increase the costs of both development and acquisition. Here, too, the Responsible Office needs to be designated, and the number of bureaucrats required to sign off (and the number permitted to sign off) need to be reduced, with the others (particularly the erstwhile required signers) returned to the private sector.
The Pentagon moves need especially to be centered on reducing the civilian workforce and on increasing the role and the responsibility of the Combatant, Transportation, and Materiel Commands, with the Combatant commanders being the sole definers of their requirements and numbers, Transportation and Materiel being the definers of the requirements and numbers needed to satisfy the Combatants’ requirements.
The moves and cuts need to be draconian, too; half measures will only perpetuate the current waste and opportunities for waste.