The Trump Administration’s implementation of its America First Energy Plan, whose goal is achieving U.S. “energy dominance,” has relied heavily upon public mineral development. Mineral development on federal lands is largely governed by statute. The statutory legal mechanisms by which the Executive Branch can “open” or “close” an area of federal lands to mineral development, whether onshore or offshore, are withdrawal, modification, and revocation. The Federal Land Policy and Management Act (FLPMA) and the Outer Continental Shelf Lands Act (OCSLA) are the primary statutes that govern onshore and offshore mineral development on over 2 billion acres of federal lands. Both FLPMA and OCSLA authorize withdrawals, which the Executive can use to place federal lands off limits to mineral development. FLPMA also authorizes modifications and revocations, which can remove constraints on such development. The Trump Administration has relied on both statutes in its quest to expand the areas that are available for private mineral disposition through modification or revocation of withdrawals by prior administrations. The authority provided by FLPMA and OCSLA to determine the availability of federal lands for mineral development is subject to a series of substantive and procedural constraints. Because it regards those constraints as undesirable shackles on the implementation of its mineral development policies, and consistent with its expansive view of Executive Branch power in almost all contexts, the Administration has not been content to rely on statutory authorization to modify and revoke development-precluding withdrawals. Instead, it has also invoked non-statutory, implied or inherent authority to open vast areas of federal lands to oil and gas, coal, and other mineral development. The paucity of judicial precedent governing the parameters of statutory and non-statutory Executive Branch authority to reopen lands previously placed off limits to mineral development raises significant questions about the legality of the Administration’s efforts to alter the status of protected lands and resources. Although the Administration apparently regards downsizing or revocation of withdrawals by previous administrations as a quick and effective way to open up vast new acreage to mineral development, the legal basis for its actions is tenuous at best. This Article examines both statutory and non-statutory mechanisms for determining the availability of federal onshore and offshore lands for uses such as mineral exploration and development. It identifies the constraints that FLPMA and OCSLA impose on revocation or modification of previous withdrawals. It also explores the parameters of non-statutory Executive mineral disposition authority and assesses the legality of the significant Trump Administration withdrawal modification and revocation efforts to date. It concludes that Congress has eliminated any implied or inherent withdrawal, revocation, or modification authority that may once have existed. It also finds that the most prominent and controversial of the Trump withdrawal modifications and revocations exceeded the authority the Executive Branch retains under FLPMA and OCSLA. As a result, that the Trump Administration’s unauthorized pursuit of energy dominance should result in judicial invalidation.