exclusive to one department, we have also used the terms “primary,” “core,” or “essential.” See Salt Lake City v. Ohms, 881 P.2d 844, 849 (Utah 1994); Timpanogos Planning & Water Management Agency v. Central Utah Water Conservancy Dist., 690 P.2d 562, 567 (Utah 1984); State v. Gallion, 572 P.2d 683, 688 (Utah 1977). But we have never been willing to be more precise than this. See Thatcher v. Industrial Comm’n, 115 Utah 568, 207 P.2d 178 (1944). A necessary corollary to the doctrine that some powers or functions belong exclusively to the members of one branch is that there must be powers and functions which may, in appearance, have characteristics of an inherent function of one branch but which may be permissibly exercised by another branch. See Matheson I, 641 P.2d 674, 676 (Utah 1982) (<HOLDING>); see also Taylor v. Lee, 119 Utah 302, 226
recognizing that immigration policy is the clear purview of the legislative branch recognizing as a matter of law executive privilege for governor holding that narrowing of field of potential judicial appointees before governor appoints partakes of elements of the appointment power but is not so inherently an executive function as to preclude participation by the legislative branch in that narrowing recognizing power of appointment does not rest exclusively in any one branch holding that the qui tam provisions do not usurp the executive litigating function because the statute gives the executive branch substantial control over the litigation