Donald J. Trump and his allies are planning a sweeping expansion of presidential power over the machinery of government if voters return him to the White House in 2025, reshaping the structure of the executive branch to concentrate far greater authority directly in his hands.

Their plans to centralize more power in the Oval Office stretch far beyond the former president’s recent remarks that he would order a criminal investigation into his political rival, President Biden, signaling his intent to end the post-Watergate norm of Justice Department independence from White House political control.

Mr. Trump and his associates have a broader goal: to alter the balance of power by increasing the president’s authority over every part of the federal government that now operates, by either law or tradition, with any measure of independence from political interference by the White House, according to a review […]