I am not sure about selling federal land. To often it is “sold” to a non profit or connected group that then destroys it. Now, in New Mexico most of the scrub ground isn't worth much, but there are down sides to selling the land. Once you sell an asset, you don't get it back.
This wouldn't be like the deal where the little old lady donates her family farm to the Sierra Club and they turn around and swap the farm for some other piece of public land they prefer (like with the endangered treetop toad).
This would be a much more organized use of public lands to BACK public debt, and at the margins where sales would be required to raise cash or redeem other bonds (as in a "default swap" eh) there'd be a transfer of value if not necessarily of a specific piece of property.
Any time it was necessary to redeem a bond certain lands would be marketed ~
That's a win-win every time.