Four national monuments in the American West could be shrunk and six others opened up to permit more mining, grazing, logging, and commercial fishing if President Trump follows the recommendations of Interior Secretary Ryan Zinke.

The monuments recommended for downsizing include red rock canyons in Utah, forest and grassland in Oregon, and stunning rock formations in Nevada.

If enacted, the modifications would represent the most sweeping changes to existing national monuments by any sitting president — and are sure to set off a legal battle over presidential powers likely to reach the U.S. Supreme Court.

Zinke’s advice is contained in a 19-page memorandum sent to the president late last month, after a review of 27 monuments at least 100,000 acres or more in