Hm, thanks for the corrections. I think the NPS is currently what everyone's talking about because of the scale of Bears Ears. Does that conform to your experience?
In my experience (11 years NPS, 5 years BLM, 9 [and counting] with USFS), each NPS superintendent has much more discretion than any BLM or USFS counterpart in most things not related to wildland fire.
But then again, Bears Ears is BLM, not NPS.
Creation of that National Monument was an Antiquities Act authorized "proclamation" (essentially an Executive Order). Most agency input would have been from Senior Executive Service political appointees (Obama admin), with information (but few opinions) provided by on-site career staff as requested. Then a Management Plan EIS done by regular civil service staff, but obviously constrained by the specific wording of the proclamation. That was mostly all BLM but probably some input from the NPS as they're the experts on the Antiquities Act - but then again this was not BLM's first NM, they have experience of their own.
Then a White House (Trump admin) Executive Order to review a number of Antiquities Act authorized designations. Followed by an order from the President to reduce the size of the monument. I am not sure what sort of "order" that the reduction was was. Like I don't know if it was an Executive Order in its own merit or something else or something tiered off of the previous Executive Order to review designations. That would have likely kicked off a new round of management planning by the career civil service staff.
The a Biden admin EO to review the reduction in size that the Trump admin had ordered. This proceeding alongside lawsuit activity challenging the previous administration's reduction of the boundaries (which apparently had never happened before with Antiquities Act designated NMs), followed by restoration of the original (Obama admin) boundaries.
So most of what you are hearing about was probably the original designation, mostly driven by people at the very upper levels. It was a political decision, not administrative. Then local staff development of the Management Plan tiering off Antiquities Act and Federal Lands Policy and Management Act, and Omnibus Public Lands Management Act - administrative (not political) but tiering off of laws and EOs which were obviously developed via political processes.