In this first year of his second term, President Donald Trump has claimed broad powers to unilaterally restructure much of how the U.S. government functions. Some of these assertions have gone completely unchallenged. Others have been litigated, and although lower courts have been skeptical of many of these efforts, the Supreme Court has been more approving. Trump has taken as much advantage of his new powers as he plausibly can, prosecuting his political enemies, firing independent agency heads, and dismantling federal agencies almost at a whim. One salient question now is: When and if the Democrats return to power, how...