150 Militia Take Over Makhuer National Wildlife Preserve Headquarters

[Ares]

Is there any evidence that the Federal government got approval from the legislature of Oregon State and actually paid money for the property?

I doubt it.

Article 1 Section 8 Clause 17 stipulates that the Federal Government is only allowed to legislate and control land within the 10 mile square of The District of Columbia. Unless the land was sold to DC : "and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings;-" Like you said I highly doubt the Oregon legislature willingly sold off over half of the state to the Federal Government.

So under what authority or Jurisdiction does the Federal Government have? Imaginary jurisdiction if you ask me.